Anyone know the Highest WHP/TQ for someone using GT40 heads? I wanna set a goal to be the highest in a street engine N/A of course. And most guys are running autos anyways. Ive heard people say you cant make more than 300 with these heads, but ive seen plenty of guys do it. I think 350/360 is a safe number to shoot for. Ive got a lot of tricks planned for it.
oh and 260/255/289/302/306 only, no windsors So far the highest i have found is one at 326/357, and it wasnt a crazy build at all. But it was a manual, also it wasnt a mustang dyno. I know how notorious those are for adding HP.
are there people laying claim to this? will it be worth the time and expence to make those heads flow enough? i think thats why people arnt makeing more power that what your finding.
No one is, but ill never be able to have the most powerfull maverick or sbf for that matter. Its still going to be a budget build, but at least it can have a small claim to fame. Nothing fancy on the heads either, plan is to just spend 200 on them(getting the machine work for free) gasket match the intake and port the exhaust. Its also a mule engine for some things that ive picked up lately but ive never seen anyone do them on this forum. If they work its just icing on the cake, if they dont its just a lesson learned. Most of them are free, and the others are relatively cheap.
im lookin at the gt40 heads along with a e303 cam atop a blue print 347. throw in a edl intake # 2121, and a holley 600 #4776 just for good a topper.
I'm running GT40 heads that I had milled down .020 . When I had them on my cougar they made a noticeable difference compared to the E7s that were on it. I'm running EFI on my maverick and with stock 185/75/14 tires and peddling the he'll out of it to get traction I ran a 14.34 at 99.91mph. Very good heads for a budget build.
That 347 should make power down low, unlike the one im building. This one is going to rev, I already have a stealth intake thats getting work. The cam im going to use is coming from delta, a hyd roller 224/234 .542/.563.
Are you talking dyno numbers or timeslips? There are some pretty impressive dyno runs and timeslips on corral. There is a couple guys by screen name of tinman and noslow (i think) that are really doing well. . I love gt-40/gt-40p set ups! Seems like the best so far are with tfs-1 cams or ed curtis/ buddy rawls camshafts. Here is some reading http://forums.corral.net/forums/showthread.php?t=1014187 http://forums.corral.net/forums/showthread.php?t=1270602 http://forums.corral.net/forums/showthread.php?t=1269774 And my personal favorite http://forums.corral.net/forums/showthread.php?t=1263569
im sure you know to get the right vavle springs for that cam and check piston to valve clearance. ive heard some people talk about angle milling the heads give some sort of good gain. i dont know the reasons but you may want to look into that also.
74 GRABBER thank you! Ill check them out! And yes Bryant aftermarket springs will be used, I think the cam is a clone of an old trick flow cam. So im going to ask on the mustangs board. The guy doing my machine work also has the tools to test springs and sim them, etc. That and the pistons are the only things that are going to be bought. Everything else i already have or will make. I have access to a welder and im not afraid to cut up a set of 6901s I was gonna do it anyways to get more ground clearance. But trying a different collector might be fun. Or even a 4-2-1.
Holy $#|t, that ten second factory stock foxbody is insane. My goal was 12.50 lol, i have nothing on that car. But I think a 350WHP street maverick should run mid twelves.
Having built a couple 347's myself, IMO your parts selection would be "OK" for a 302 but will really choke a 347. You need to think of a 347 more as a 351, not a 302 anymore. The old saying for 302 strokers is "Use 302 parts and get 302 power".
LOL yeah thats nuts, but think how much money them guys have into just a set of heads. I would think a properly equipted maverick working with good suspension and weight reduction it would be possible for an 11 second slip using gt-40 heads I also wouldn't get ahead of yourself shooting for 350WHP, I would say 275RWHP is a good starting point. What transmission you running?
my goal realisticly is more like 300. Then maybe do stages to see if it can go up from there. I havent decided yet. I can choose between a C4 or a T5. Rear end hopefully a 8.8 31spline with 373 gears. Im in the process of selling off my 8 right now. Since it wont fit my wheels anyways.
