[magnumpi]

With my tax return I'm buying some aluminum heads to use on the 398 stroker im building. I think I've got it narrowed down to 2 different heads.

I initally thought I would just get some GT-40 "x" heads. They seemed to have worked good for other people. I got to doin some research on them and noticed that the exhuast vavles, and exhasut ports were a little smaller than some of the similar priced heads. And the intake ports were slightly smaller too.

So i got to doin some lookin and found these trick flow heads at summit. They seem better than the gt-40s and have the right size chamber (64cc) to keep my 10.5:1 CR.

Anyway heres the trick flows:
http://store.summitracing.com/partd...4294889096+4294867079+4294867005&autoview=sku
Intake Runner Volume (cc): 192
Exhaust Runner Volume (cc): 87
Intake Valve Diameter (in): 2.020
Exhaust Valve Diameter (in): 1.600

And heres the good ole gt-40 "x"s:
http://store.summitracing.com/partd...4294889096+4294867079+4294867005&autoview=sku
Intake Runner Volume (cc): 178
Exhaust Runner Volume (cc): 62
Intake Valve Diameter (in): 1.940
Exhaust Valve Diameter (in): 1.540

I am a true noob to building engines so maybe im missing something simple. They are virtually the same price, within a few dollars of each other. So which one is gonna be the better head?

This will be used on a 351w block with a 393 stroker cast crank, forged i beam 5.956 rods, forged -4.8cc flat top pistons, .060 bore for a total displacement of 398 cu in. 10.5:1 CR, carburated. Will move to fuel injection later on.

So what do yall think? Gacknar, i know you must have some input on this

Thanks for puttin up with all my noob motor questions
Josh

 

[BigNorm]

My first question is: What are you building the engine for? My second is why aluminum? Granted aluminum is cool but if you're putting it in a 5000 lb vehicle then what are you trying to acomplish. I know that aluminum displaces heat faster but our Broncos being what they are... BIG, there's plenty of room for a bigger radiator that will acomplish your purpose. The reason I mention this is that aftermarket heads as I'm sure you've figured out are EXPENSIVE. Aluminum ones are REAL EXPENSIVE. If you are wanting a set of heads I'd check into some World Products cast iron heads. I believe they'll machine the valves to whatever size you need. Third and my personal choice (I'm cheap) is ebay. Keep an eye out for people who've spent the money to have there heads done already. Often times you'll pay alot less than if you bought them new. Sometimes you can find ones that have never been installed. Believe me I know the excitement of engine building and how expensive it can get. I commend you on actually shopping for heads because that is where your power will be found. I've researched some stroker builds in the past and here are some of the links:

http://bbs.off-road.com/ubbthreads/showflat.php?Cat=&Board=offroadfordbroncolate&Number=997214&Forum#Post997214

http://www.abysmal.com/bronco/engine/Engine.html

http://www.fuelairspark.com/

http://www.pricemotorsport.com/Intake_Manifolds/Clevor2v/clevor2v.html
http://www.dallasexportsales.com/DESCatalog/page-6-Cranks.html
http://www.speedomotive.com/Stroker%20Kits.htm
http://www.strokerkits.com/?source=bookmark
http://bbs.off-road.com/ubbthreads/showflat.php?Cat=&Board=offroadfordbroncolate&Number=1106337&page=0&view=collapsed&sb=5&o=31&fpart=1

Some of the info deals with putting Cleveland or M heads on a small block but overall there's alot of information and vendors to ponder over. I hope this is a small help.

 

[magnumpi]

It will go in my bronco. I've always wanted a high-po motor, because my dad allways tinkered with them when i was younger. From what I've read i will need aluminum heads to safely run without pinging on premium the 10.5:1 compression ratio i plan to achieve. I know its expensive, but its what i want, and I, myself, am paying for it. I also plan on puttin in a large 4 core radiator to replace what looks to be a *gasp* one core radiator that was in my bronco (dunno for sure what size it its but its skinny).

I will begin reading all the links you gave me, should keep me entertained tonight

Thanks
Josh

edit* I've been lookin out on corral.net and ebay for used heads/rebuilt ones for sale too. Ive seen some good deals but didn't have the money at the time

 

[BigNorm]

Damn you replied fast. What the hell do you need 10.5:1 for? Are you going to inject it. Some of those links were to sites that program chips I believe. Could be wrong. It's been awhile since I've read them. If you aren't worried with the price of gas why don't you just go all out and stroke a 460? I don't believe I've seen a 502 CID Bronco yet. :shocked
It sounds like your dead set on blowing big dinero. If that's the ticket then there's no replacement for cubic inch displacement.

 

[magnumpi]

Damn you replied fast. What the hell do you need 10.5:1 for? Are you going to inject it. Some of those links were to sites that program chips I believe. Could be wrong. It's been awhile since I've read them. If you aren't worried with the price of gas why don't you just go all out and stroke a 460? I don't believe I've seen a 502 CID Bronco yet. :shocked
It sounds like your dead set on blowing big dinero. If that's the ticket then there's no replacement for cubic inch displacement.

yeah im bored, so ive been lookin up motor stuff and checkin for replies.

To be prefectly honest when i started buying parts i didn't know what i was gettin into. I thought a 460 block would be too hard to find and i would need a new trans, and thought big block parts would be insane expensive(some are), so thats why i didn't go that route. Now that i've learned more, i found that 351w blocks particullary roller ones are pretty rare right now, and 460s are easier to find. I saw 3 in the junkyard last time i went. Anyway, a few months ago I found some good deals on on an Eagle cast crank, and forged rods and bought those. I didn't go with a bigger stroke because it was a little bit of a price jump, and i didn't want to spend the money at the time.(at that time i was still gonna use iron heads and it was still a "budget build" In retrospect, your right, i should have probably went with a stroked 460 because i've turned into a power junkie.

I had done some research on heads and figured i would go with gt-40x alumn heads because i thought i could find a good deal on a used set probably and the new ones weren't as expensive as most of the other. I then went and bought some keith black .060 over flat top -4.8cc forged pistons, which with the combustion chambers of the gt-40s gave me 10.5:1 compression.

This isn't a daily driver so i started with the intent of running as high as a compression as possible on pump gas to get as much power as possible out of the motor. I don't mind spending the money on the good stuff at the pump.

So basically what happened was this thing started out as a "budget" stroker build. And i kind of went power hungry with it. If i had it to do over again i would research more and probably would have stroked a 460. But i've already spent a grand on parts, and i'm confident that i will be happy with the results. Someday down the road I'll drop a stroked 460 in 'er, but not anytime soon.

edit* it will be FI later on down the road. But i will just run my current edelbrock intake and new holley carb that i got right before i pulled the old 351w from it

 

[RLKBOB]

I wouldn't go with the TFS heads you listed. I would recommend TFS Twisted Wedge or similar(not just because that's what I have). The ones you listed have an intake runner of 192cc. For our big trucks we don't usually have very high revving engines. That 192cc intake runner will push your power band up some in the rpm range. To keep the power band as close to idle-1,500 rpm you should stay between 170 and 180cc. I disagree with staying with cast iron heads. I also looked at the pros and cons of alum vs. iron and felt that alum was best for what I "wanted". Keep lookin if you have time, I got my TW heads from Summit for $815 last Feb on sale. I looked for months on ebay and other places and never even found a pair of comparable used heads for that price. I realize that the TW heads have a 61cc combustion chamber that will make the compression a little higher, you'd have to do the math to see how high. I can tell you that my 351 with these heads and 13cc dish pistons gives me about 9.3:1 comp. Is your short block already assembled(i.e. are you locked into those pistons)? The GT-40's are good heads also. Have you looked at AFR or any of the other major names? One thing to keep in mind if you look on ebay is if the heads have been ported. If you can get a set with a stage 1 or 2 porting job for about the same price as unported new set that would be a great deal.

 

[RLKBOB]

Someday down the road I'll drop a stroked 460 in 'er, but not anytime soon.

No you won't. You'll still be very happy with the engine you're building.

The only reason I didn't do a 393 was because I didn't want to have to convert over to MAF or need a TwEECer to tune it. I did as much as I could to my engine that still allowed me to keep speed density w/o a tuner and I'm very pleased. From the sounds of it you're doing about the same thing and you'll be pleased too.

 

[magnumpi]

Bob, thanks for the info on the heads. I knew they bigger intake ports meant more top end, but i didn't know it would affect it that much.

I also somehow missed the twisted wedge heads, after some calculations, and a slight gasket thickness adjustment i could run them with a 10.66:1 CR or 10.47:1 CR depending on the thinkness i use.

I am kind of locked into the pistons since i already dropped the bills on them, but i think they will work with some of the lower combustion chamber heads, from what i said above.

You are a lucky man gettin that good of a deal on alumn heads. I haven't seen a good used set for under 950 yet.

Anyone else got any input?

 

[BigNorm]

You guys spent more on heads then I did my last engine rebuild. I too built my engine to produce torque in the 500-1200 rpm range... for under $700. I can understand spending big money on heads if you are going to live past 4000 rpm on a regular basis. I'm thinking mud drags if you're in a bronco. I can't see spending 800 in heads alone on something that's not going to see 6000rpm. But whatever floats your boat. Believe me I know what you're going through. I spent around $5000 on my mustang motor when I was in the army. I installed 400M heads on a 302 and brother that sumbitch would scream. It was like hitting another gear at 4000 rpm. When you start building your baby its an addiction (or at least for me it is) I love all other aspects to this sport but nothing is more sacred than the engine build. I didn't drop the bank on my last build but loving care was put into each part of the build. I bough a set of remanufactured heads on ebay for cheaper than I could rebuild my old ones (cool! spares!) I spent a little extra on a high volume oil pump and a double roller chain. Oh and an Comp Cam (PN 35-231-3) I reused the stock intake and I'm running an autolite 2100 off of a 71 P/U. It's a great combo for what I built it for: going slow off camber but with some nice low end grunt when I need it.

I'm not saying that building high end race motors is stupid. (Because as I said they're addictive) I'm just saying keep in mind the end goal, whatever that may be. Mudding, crawling. For every excess you handicap yourself one way or another. ie: the more I modify my truck the less streetable it becomes, but man oh man is it cool in the dirt. Which is OK since that was why I built it the way I did. Nuff said. :drinkbud

 

[Dallasbronco]

Bob is right, and Norm, I think you're off-base. Dollar for dollar, a set of replacement heads will do more for that motor than any other mod. Factory Ford heads are notorious for their poor port design, particularly the smog-era heads (as in the 400M). Keeping the intake runner volume small is very desirable for a carbureted engine where the goal is low-end torque. The Twisted Wedge heads are great and I wish I could have gotten the deal that Bob did. I have Edelbrock Performer heads on the 302 currently in my Bronco and on the 351W that I'm building for the Bronco. The 302 will be re-used in my Jeep CJ.

 

[Gacknar]

I wouldn't go with the TFS heads you listed. I would recommend TFS Twisted Wedge or similar(not just because that's what I have). The ones you listed have an intake runner of 192cc. For our big trucks we don't usually have very high revving engines. That 192cc intake runner will push your power band up some in the rpm range.

Yes but having the greater displacement of a 393 will help bring it back down some.

Question
Have you considered valve clearance for larger aftermarket valves and your flat top pistons. I belive you run into even grater problems with twisted wedge heads. Do your pistons have valve relif cut in them?

I can't see spending 800 in heads alone on something that's not going to see 6000rpm.

Heads are what make an engine, no matter what RPM goals you have. You just have to choose the right ones for yur goals.

 

[bmc69]

Bob is right, and Norm, I think you're off-base. Dollar for dollar, a set of replacement heads will do more for that motor than any other mod. Factory Ford heads are notorious for their poor port design, particularly the smog-era heads (as in the 400M). Keeping the intake runner volume small is very desirable for a carbureted engine where the goal is low-end torque. The Twisted Wedge heads are great and I wish I could have gotten the deal that Bob did. I have Edelbrock Performer heads on the 302 currently in my Bronco and on the 351W that I'm building for the Bronco. The 302 will be re-used in my Jeep CJ.

??. The 400 heads are 351C-2V heads and the early ones had no Thermactor ports or any other other smog acoutrements..they were pre-smog designs afterall. The ONLY thing Ford ever did later to those heads, smog-wise, was add the Thermactor passages and increase the chamber volume slightly. They were the 'head of choice' for years whjen building Clevor engines and still are in many cases. The Engine Masters competition sees a lot of the 351C-2V and aftermarket derviatives in play. The canted-valve oval-port design is a known good thing.

 

[Dallasbronco]

400M heads and 351C heads will interchange, but they are not the same. The M motors didn't come out until 77 as a big-block replacement and as such have always been plagued with a restrictive intake port runner. M heads can be used for Clevor builds but only if you do alot of port work to them.

 

[bmc69]

The M motors didn't come out until 77 as a big-block replacement and as such have always been plagued with a restrictive intake port runner.

Not sure where you are getting yr info. First, the 400 is not an 'M' motor..that designation only applied to the 335-series 351 when they came out (in '75), to differentiate them from the 351W. The 351m is indeed a 'smog motor'..in that it is simply a destroked 400 with low cmopression and Thermactor heads.

The 400 came out in 1971. I build a lot of them and have plenty of the D1 production castings..both blocks and heads..in stock. Good stuff to work with. Even the post-75 head castings are fine for anything bu all-out drag racing. However, most of the engines we build are fitted with the Australian 302c/351c-2V closed-chamber heads to get the compression back up to decent number.

 

[bmc69]

Sorry for the hijack, BTW. I'm guessing that a 'Clevor' build was not one of the options under consideration in this particular case.:toothless (they sure do work well though, especially for higher-RPM apps)

 

[BigNorm]

??. The 400 heads are 351C-2V heads and the early ones had no Thermactor ports or any other other smog acoutrements..they were pre-smog designs afterall. The ONLY thing Ford ever did later to those heads, smog-wise, was add the Thermactor passages and increase the chamber volume slightly. They were the 'head of choice' for years whjen building Clevor engines and still are in many cases. The Engine Masters competition sees a lot of the 351C-2V and aftermarket derviatives in play. The canted-valve oval-port design is a known good thing.

Thank YOU BMC! I can't believe I'm being called a lyer why I've used those exact heads on my old mustang's 302. They are an awsome fix for a high horsepower high rpm engine. The intake ports on the cleveland/ 351/400M engines are twice the size of stock windsor ports. How on earth can twice the voluum be restrictive? You said another thing which I agree with.

Keeping the intake runner volume small is very desirable for a carbureted engine where the goal is low-end torque.

Guess what? stock heads have small intake runner. I agree that high horsepower will be achieved with high volume heads. But as you said that's going to jump your curve into the higher rpm range. ie: my 302 w/ 400M heads would take off like I had just downshifted when I hit 4000 rpm. I had that car up to at least 140 one day and it had no intention of slowing down when I took my foot off the gas. (stupid yes, but it's there nonetheless) I've heard of guys having good results with the 70s era 351W heads and bumping the intake valve open a size or two. Where's the mud drag guys? They would have an idea of what you would want to try out. no doubt they'll say a 460 but that 396 your building sure will be sweet. I don't want to argue about high dollar heads. I'm just trying to make you look at the options and think some before you spend any more cash. I'm sure gearing will go alot into your decision as well. If you're geared low to where you can reach those high revs fast then it may work out good for you. I don't doubt it'd be fun to drive.

 

[bmc69]

Yr welcome Norm..no worries.

I should have mentioned that the "M" designation for the destroked 400 (351M) was added to differentiate it from the 351W AND the 351C. The only difference between the '71 400 heads and the 351C-2v heads was the addition of 2.7 cc of chamber volume. Thre was typically that much variation between castings with the same casting number ibn later years..seems that the Cleveland (CF), Michigan (MCC) and Dearborn (DF) foundries all ended up witha different result from the 'same' mold.

 

[magnumpi]

Question
Have you considered valve clearance for larger aftermarket valves and your flat top pistons. I belive you run into even grater problems with twisted wedge heads. Do your pistons have valve relif cut in them?

Heads are what make an engine, no matter what RPM goals you have. You just have to choose the right ones for yur goals.

I haven't really thought abuot that part actually im glad you mentioned it. The pistons do have vavle reliefs cut in them. So i guess maybe they should be called mini-dish? they were listed as flat tops thou.

How would i go about checking for clearance issues? Is it something that would have to be done during assembly, or capable to determine thru calculations?

Also, does anyone know where i could get the desktopdyno files for the above heads so i can get an idea of how well each works with my setup?

Thanks for the help so far
Josh

 

[magnumpi]

Guess what? stock heads have small intake runner. I agree that high horsepower will be achieved with high volume heads. But as you said that's going to jump your curve into the higher rpm range. ie: my 302 w/ 400M heads would take off like I had just downshifted when I hit 4000 rpm. I had that car up to at least 140 one day and it had no intention of slowing down when I took my foot off the gas. (stupid yes, but it's there nonetheless) I've heard of guys having good results with the 70s era 351W heads and bumping the intake valve open a size or two. Where's the mud drag guys? They would have an idea of what you would want to try out. no doubt they'll say a 460 but that 396 your building sure will be sweet. I don't want to argue about high dollar heads. I'm just trying to make you look at the options and think some before you spend any more cash. I'm sure gearing will go alot into your decision as well. If you're geared low to where you can reach those high revs fast then it may work out good for you. I don't doubt it'd be fun to drive.

Thanks for the info Norm. I thought about using stock irons like i had said before but to me it just didn't seem worth the money. I would have to run a lower compression ratio, and also another thing i didn't mention was i would probably have to have any used heads competly rebuilt. Because it would scare me not really knowing what they were used for before i got them. So i figured after all of that i could put a couple hundred more with it and get some new alums.

I will look into using some of those older 70s heads thou, that is def. interesting

oh and gearing, i didn't even consider that too much. I'm def. a noob as you can tell :brownbag I will be using pretty steep gears thou. Either 4.88s or 5.13's with 36s after i put my lift on. So that will probably help some too.

Now if i can just figure out this cylinder head thing...

 

[Gacknar]

How would i go about checking for clearance issues? Is it something that would have to be done during assembly, or capable to determine thru calculations?

http://www.fordmuscle.com/fundamentals/pistontovalve/index.shtml