thinking about ordering a set of aluminum gt-40 heads. should i worry about any stretching or anything else with the two different metals?
Precisely what is so bad about GT-40 "X" heads? I would like to know before I spend a lot of time installing my engine with these heads on it.BuckingBronco93 said:Fawk GT40, save yourself some time, get either AFR's 180 or TrickFlows Twisted Wedge heads, or Brodix. Top of the line for better performance is allways smart!
GacknerGacknar said:Precisely what is so bad about GT-40 "X" heads? I would like to know before I spend a lot of time installing my engine with these heads on it.
Oh and AFR doesnt make a 180 head for Ford small blocks.
Quote: 405 hp at 6,200 rpm and 380 lb-ft of torque at 4,300,Sixlitre said:
badpony93 said:are gt 40 heads any better than stock heads? i'm not building a race car i don't need a set of 2500 3000 dollar heads, im good spending a grand and upgraded set of heads. i was just wondering if bolting a set of aluminum heads to a cast iron block should cause an concern
badpony93 said:ok how about the gt-40p heads? or should i reach into the pockets. now keep in mind, it's a DD, weekend warrior but would like to be able to feel the power.
AFR makes some of the best performance heads in the world. The proper set of AFR heads will do absolute wonders for your Hi performance automobile. There is a good chance I will be placing AFRs on my Mustang.Sixlitre said:
But see, here is the problemCarCraft said:278 hp at 5,200 rpm and 315 lb-ft of torque at 4,100 on Westech Performance's SuperFlow 901 engine dyno.
See what happened there?CarCraft said:(with AFR 165) the little 302 produced a jaw-dropping 382 hp at 6,000 rpm and 368 lb-ft of torque at 4,200, a gain of 104 hp and 53 lb-ft solely from the heads and headers
Actualy with Aluminum you can get away with a higher compresion ratio than with Iron. That means more power on less expensive gas.93XLT said:With our Bronco's the only difference it will make is in your wallet. Besides aluminum is much more prone to warping and causing a blown head gasket.
Gacknar said:AFR makes some of the best performance heads in the world. The proper set of AFR heads will do absolute wonders for your Hi performance automobile. There is a good chance I will be placing AFRs on my Mustang.
But my Mustang doesn't way 6,000lbs
Here is what the car in the artical put out before the heads.
But see, here is the problem
See what happened there?
How often do you have your Bronco at 6,000rpm?
And 4,200 is a little high as well.
AFR 165's are greate in a light mustang with a mild 302, but they are too much head for a low reving 302 in a Bronco.
165's where to little head for my 351. AFR 185's where to much, I would have lost torqe with a 185cc intake runner and the 2.02 intake valve was to much for my engine. It would have moved my power band to high in the RPM range for my goals. The 185 also has a combustion chamber size of 58cc or 61cc, that would have put me at or over 10:1 compresion with my pistons, wich is higher than I wanted to try running on 87 octane pump gas.
My GT-40"X" heads have a 178cc intake runners and 1.94 intake valve. Exhaust runner volume is 62cc and it has a 1.54 exhaust valve. These heads also have a 64cc combustion chamber wich put me right around my 9.5:1 compresion goals. This head fals right between the AFR 165 and 185.
I ran many simulations with Desktop Dyno. For what I wanted, the GT-40 "X" heads gave the best tourqe and HP curve for my aplication. (Cam, Bore, stroke, etc etc) RLKBOB did the same but found that with his engine combination TFS heads gave him the results he was looking for. (his engine runs a diferant cam and he wanted a higher compresion ratio) So he whent with TFS heads.
You go with the parts that work best for you, not that work best on someone elses engine, in a completly diferant aplication. (I.E., Mustang to Bronco)
Choosing the right head involves more than just bying a certain brand. You have to take your engine and your goals into consideration. You want engine parts that complament each other.