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Discussion Starter · #1 ·
Im new to this so forgive me if i say something put of place. I found a good and reliable guy that prides his work and need advice. My block and heads are going to the machine shop and i want them to be honed or bored out for a smooth true surface for the cylinders. Will it be worth it to upgrade my intake for more air flow? I dont want to go crazy with more HP or TQ, just a little above stock. Its a speed density 351w efi. Whats the benefit of having the engine bored or honed besides being true again.
 

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get a price on the heads first, it MIGHT be worth going with different heads. GT40 or aftermarket. hate to see +700$ go into stock heads when you can get more for that money. if its around 300ish then its more worthy if you arnt looking for much more power. aluminum will always be more expensive but you can sometimes find GT40 heads for a good price and at least gain some power while staying OE heads

if you do a rebuild on a block with any substantial milage, you pretty much want to have the block bored if you want the engine to be proper. it wont gain almost any power, boring only add a handfull more cubic inches, but it will ensure you will retain power and not loose it from rings not sealing correctly due to egg shaped uneven loose bores.

a new intake will add some power, the stock 351w intake is trash. but the only direct replacement intake is $900 and throttle bodies are $400. so unless you plan on making decent power or going Mustang style aftermarekt intake, i jsut stay stock.

performance is a slippery slope. but you MIGHT consider stroking the engine. bore might not add much but stroke does. 408 builds are popular and make much more torque and can make more power. the problem with doing a stroker is you almost required to put better heads and intake on or else it will be very bottlenecked. andif you are going to od that, you will probably need a tune, larger injectors, good exhaust, so on and so forth
 

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but just realizing your username, i am assuming you are in California and emissions is going to be an issue. so you might jsut stay stockish build or put GT40 heads on. you CAN build more performance builds while being emmishion legal but its gonig to be expensive due to CARB EO parts
 

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1987 Bronco 351W, C6
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While it's getting rebuilt, you should put a better camshaft in. Several threads on here about what works with SD EFI. There are many aftermarket cams out there that will work well and give you a better power band than the stock bumpstick. Match that with whatever you do headwise.
 

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Discussion Starter · #5 ·
but just realizing your username, i am assuming you are in California and emissions is going to be an issue. so you might jsut stay stockish build or put GT40 heads on. you CAN build more performance builds while being emmishion legal but its gonig to be expensive due to CARB EO parts

Yeah Kingfish999 I do have to worry about emissions, but ill look into the heads. Thanks.
 

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Discussion Starter · #6 ·
While it's getting rebuilt, you should put a better camshaft in. Several threads on here about what works with SD EFI. There are many aftermarket cams out there that will work well and give you a better power band than the stock bumpstick. Match that with whatever you do headwise.
Thanks, I'll definitely look into that. I plan on putting a good cam in it, ill do some research.
 

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theres a thread about cams. these are good for a bit of performance while keeping the engine happy. BUT idk if they might cause emissions testing issues if using a sniffer. dont go too big, but know you probably wont gain alot either
 

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Definitely want to do a new camshaft, as mentioned you're choices are very limited based off of your Speed Density EFI but there are some out there that can definitely pep up your ride. As far as the intake goes, ask your machinist about port matching the intake runners to the cylinder heads. Also as mentioned, you may can find some better ones for around the same money, but I don't think you're going to notice a ton of difference, just know that your heads, cam, and intake need to work in harmony with one another.

You can also port match the upper intake to the lower intake.

I have always done port matching, it's basically "free" horsepower if you do it yourself.

Also, im not sure about this next suggestion but you may can get by with smoothing out the thermactor bumps, but it will effect emissions, but im not sure how much it will, the thermactor system would technically still be in place and functional, but not sure how much impact it has without the bumps....

Anything that can help assist in the flow of air IN or OUT of the engine is going to help.
 

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Discussion Starter · #9 ·
Definitely want to do a new camshaft, as mentioned you're choices are very limited based off of your Speed Density EFI but there are some out there that can definitely pep up your ride. As far as the intake goes, ask your machinist about port matching the intake runners to the cylinder heads. Also as mentioned, you may can find some better ones for around the same money, but I don't think you're going to notice a ton of difference, just know that your heads, cam, and intake need to work in harmony with one another.

You can also port match the upper intake to the lower intake.

I have always done port matching, it's basically "free" horsepower if you do it yourself.

Also, im not sure about this next suggestion but you may can get by with smoothing out the thermactor bumps, but it will effect emissions, but im not sure how much it will, the thermactor system would technically still be in place and functional, but not sure how much impact it has without the bumps....

Anything that can help assist in the flow of air IN or OUT of the engine is going to help.

Thanks for the info, I might just try and find some gt40 heads. How does port matching the upper and lower intake work exactly? I didnt think they could do that. Ill go ahead and read up on new cam as well.
 

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Port matching is when they take an intake gasket and make all the ports on the head side and the ports on the intake side match the gasket perfectly, so you get a smooth transition, watch a YouTube video on it, sometimes it’s called gasket matching.

Everything from the factory is “as cast” and bolted together and they have little overlaps here and there.

Also make sure you get gt40 and not gt40p heads, the spark plug holes won’t work with the gt40p without custom built headers.


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a popular mustang porter names Tmoss has some articles you can read. most are for mustangs but some are more universal articles that can help guide you to make some more performance

or on the other hand you might just consider sending him your intake to get ported. i think its around 300$ range which is significantly cheaper than aftermarket intakes. he has tons of experience with Ford intakes where a local shop might just occasionally do porting of various intakes. will be emissions legal and can help gain/support some performance. he could even port your heads but the stock E7 heads are really not worth porting. GT40 heads are commonly ported however and wouldn't be a bad idea

there is also another popular porter called BigDogs Porting who i have seen claim really good flow from the 351w truck intakes. hard to recommend him but it is an option. i know a member on here had issues with him doing heads i believe. him and Tmoss are always butting heads on the forums about porting meathods. but he does advertize stage 2 porting for about 300$ and very significant gains (177cfm stock vs 242cfm ported in one post)


something about GT40 heads i fogot about are most do not have thermactor ports. this would be needed for emission testing but i am not really sure if it is something that you can get away without having or not in Cali testing. also heads from a 302 will need headbolt holes drilled for 1/2" headbolts. not a hard thing to do for a shop but will cost more. as he said look for GT40 heads, try and avoid the GT40P heads. i think the best way to avoid these problems would be to find some heads from a Lightning engine which should have the thermactor ports and correct headbolts. but they would be harder to find. might be worth making a WantToBuy ad on mustang forums

otherwise soem AFR 165 or 185 heads would be a great head to throw on and are CARB EO. but that is defiantly expensive. like 1800$ for pair and thats not inclueding rockers or pushrods
 

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I haven't built my '94 351w yet, but my friend who has built several mustangs (including fox body) swears that putting high flow heads and intake will tremendously unlock a lot of power in these motors. I had a machine shop bore my cylinder walls 30 over, deck, hone, hot tank and magnaflux the block. They also balanced my rotating assembly. Reusing the stock crankshaft and had to have it turned due to a tiny wear spot. Using Keith Black hypereutectic flat top pistons, mahle rings, new rods. Been using desktop dyno to find a good cam, and so far a Comp Cams extreme 4x4 cam gives good torque and hp. Looking at probably going with 185cc or 195cc AFR heads (58cc chamber & assembled). Looking at the holley efi side mount ford style Hi-Ram 95mm intake manifold and accufab 95mm throttlebody + CAI. 47lb injectors. More than likely going to switch to a Holley efi terminator and us shift controller, instead of having to chip and tune the factory ECU. Deleted smog & emissions (tab/tad/egr). Also going to go with an electric fan to free up more horses. Shooting for around 10.5:1 compression & pump gas. Desktop dyno puts it roughly at 450hp and 500 ft/lb tq peak at the crank.
 

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I haven't built my '94 351w yet, but my friend who has built several mustangs (including fox body) swears that putting high flow heads and intake will tremendously unlock a lot of power in these motors. I had a machine shop bore my cylinder walls 30 over, deck, hone, hot tank and magnaflux the block. They also balanced my rotating assembly. Reusing the stock crankshaft and had to have it turned due to a tiny wear spot. Using Keith Black hypereutectic flat top pistons, mahle rings, new rods. Been using desktop dyno to find a good cam, and so far a Comp Cams extreme 4x4 cam gives good torque and hp. Looking at probably going with 185cc or 195cc AFR heads (58cc chamber & assembled). Looking at the holley efi side mount ford style Hi-Ram 95mm intake manifold and accufab 95mm throttlebody + CAI. 47lb injectors. More than likely going to switch to a Holley efi terminator and us shift controller, instead of having to chip and tune the factory ECU. Deleted smog & emissions (tab/tad/egr). Also going to go with an electric fan to free up more horses. Shooting for around 10.5:1 compression & pump gas. Desktop dyno puts it roughly at 450hp and 500 ft/lb tq peak at the crank.
I'm not 100% sure, but I don't think the comp extreme 4x4 cam is a roller cam, i think they're only flat tappet....not necessarily a bad thing, but I personally wouldnt put that much money in an engine and stick an old school flat cam in it. Missing out on a lot of range if you do that, may want to double check. Also make sure the rest of your ride is ready for the torque, like your transmission and if you have an automatic make sure you have a torque converter that is suitable for whatever cam you pick. 10.5:1 is getting up there in compression, newer engines run that all the time, but they have Variable valve timing and all that good stuff to adjust for valve knock...i had an engine built to 10.5:1 and if i didnt run 93 in it, my valves would clatter...so something to think about too.
 

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I'm not 100% sure, but I don't think the comp extreme 4x4 cam is a roller cam, i think they're only flat tappet....not necessarily a bad thing, but I personally wouldnt put that much money in an engine and stick an old school flat cam in it. Missing out on a lot of range if you do that, may want to double check. Also make sure the rest of your ride is ready for the torque, like your transmission and if you have an automatic make sure you have a torque converter that is suitable for whatever cam you pick. 10.5:1 is getting up there in compression, newer engines run that all the time, but they have Variable valve timing and all that good stuff to adjust for valve knock...i had an engine built to 10.5:1 and if i didnt run 93 in it, my valves would clatter...so something to think about too.
I don't exactly remember which cam it was, but yes I would go with a roller cam. Yeah PATC has a nice E4OD rebuild kit that comes with upgraded parts, new input shaft, and a torque converter for around $1500 last time I checked. Yeah I might run a little lower compression so that I can use 91 octane just in case. Running the theoretical numbers through a calculator puts me roughly at around 10.3:1 compression. Going to find some nice aluminum drive shafts. Already rebuilt my dana 44 and ford 8.8. The 8.8 got stronger axles, and upgraded to 4.10 gears and an Eaton Detroit Posi. Running 35x12.5 tires.
 

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Man of endless projects
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I haven't built my '94 351w yet, but my friend who has built several mustangs (including fox body) swears that putting high flow heads and intake will tremendously unlock a lot of power in these motors. I had a machine shop bore my cylinder walls 30 over, deck, hone, hot tank and magnaflux the block. They also balanced my rotating assembly. Reusing the stock crankshaft and had to have it turned due to a tiny wear spot. Using Keith Black hypereutectic flat top pistons, mahle rings, new rods. Been using desktop dyno to find a good cam, and so far a Comp Cams extreme 4x4 cam gives good torque and hp. Looking at probably going with 185cc or 195cc AFR heads (58cc chamber & assembled). Looking at the holley efi side mount ford style Hi-Ram 95mm intake manifold and accufab 95mm throttlebody + CAI. 47lb injectors. More than likely going to switch to a Holley efi terminator and us shift controller, instead of having to chip and tune the factory ECU. Deleted smog & emissions (tab/tad/egr). Also going to go with an electric fan to free up more horses. Shooting for around 10.5:1 compression & pump gas. Desktop dyno puts it roughly at 450hp and 500 ft/lb tq peak at the crank.
Holley Hi-Ram is too big on an intake for a truck based 351w build. thats really too big of an intake for any truck based build exepvt maybe a 427 stroker build. really only good for a mustang based stroker builds that use high rpm range. you will need bigger heads, custom grind cam along with a high stall converter or high axle gearing to be able to have a chance of pulling that off. but i wouldnt even try it on a stock displacement build.

which brings up another point, i would REALLY consider a custom grind cam. regardless of how built it is or not. custom cams dont cost that much more than off-the-shelf cams and will maximize your engine for your build. my recommendation is FlowTechInduction, Ed is the go-to guy on the mustang forums for cam builds. and he will be able to tell you more of what you can get away with or not as for intake and other aspects of the build. just note that he wont give you any cam info unless you pay for the cam upfront cause he doenst want his time wasted. if you are using the original 94 block then you should be F4TE and thus roller ready.

you really should have gone 408 stroker. by the time you have the crank ground, replaced the pistons, press the rods, new bearings, balance. a 408 stroker is a great way of making more power while being stronger. it does cost more in the end but if you are doing a higher end build like this thats almost the obvious choice. you can always replace top end later, but bottom end you are kinda stuck with.

just an FYI, a good performance E4OD converter alone will probably cost near if not more than 800-1500 bucks depending on stall speed and manufacture. anything less is jsut a reman stock converter and theres not many options for higher stall speed for them. my Circle D 2800-stall converter cost me $900 and that was about the cheapest. most places were significantly higher, couldnt do them, or it would take several months. my previous Monster Transmission 2400-stall converter was $900 but was not nearly the quality.

you cannot believe desktop dynos. the one i am using (DynoSim5) is such trash. its no where near accurate tho its fun to play with. but my build which is significantly more than yours it shows at 450hp 525tq. this is a 410ci engine with AFR205 heads, custom cam, and a very good intake. i expect to be making around 550hp.

this cam is for a higher rpm range than you will probably be using in your truck. 35s and 4.10 gears will not allow you to reach the rpm range to use serious HP unless you run a high stall converter. my bronco with the 410 build has 37 and 5.13 gears and a high 2800 stall converter.
 
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