Any one know how much hp you can make with the stock exhaust manifolds. The headers that were built for my 76 skyhawk are a tri-y with 1 1/2 tubes and have some very tight bends right at the head.
If you would, tell us about your engine build up or plans. Would probably give us a better idea if manifolds will work. Seems like a well ported set of manifolds (or Extrude Honed), along with a free flowing exhaust would allow some decent power. Just look at the Stock Appearing 455's!:TU: These guys are picking up around a second and a half from stock and running ported ex. manifolds!!:grin:
The car has been on the back burner for a while after my purchase of a 87 turbo-t a few years back. Now that the t is running in the mid 10s i would like to get the sky hawk back out and save some where and tear on the turbo car. The basic build is a 73 350 1970 trw forged replacement pistons it has the newer style cap screw rods with good bolts. The heads have ta big valves and were ported and gasket matched. The cam is a ta 212 and it has a ta intake with a 700 holley dp right now. The trans is a th350 that is being rebuilt right now and i am going to replace the tci 11" converter with a art carr 9" 3000 to 3200 replace the sportman pros with some 26x10 slicks and see what it does this weekend. Last time out it was in the 13.00 range. It also has a 12 bolt with 4.10 gears. The car is not driven on the street much as it has always ran hot. I also have a alum. rad on the way.:stmad:
Sounds like you've got a pretty nice build up there!!:TU: Those 1.5" primaries sound kind of small - they must give you some pretty good bottom end torque though! Seems like some ported manifolds would about equal those headers. I'd be curious to see a comparison between the two!:grin:
I am going to run them un ported and see what the difference is. There is very little room so i dont know if the driver side manifold will fit yet. I want to run the headers first with the trans rebuild and converter before i try the manifolds. The headers y into two so there is two cylinders going out a single 1 1/2" into a 2 1/2" colector. From looking at the manifolds they may work better the way they are before porting.
I have ran a Buick 350 in a H-body(Sunbird) and found that the earlier manifold will not fit the driver's side. But the mid 70's and later manifold does fit because it has a pocket for the heat shield that does not exist on the earlier ones. The steering shaft passes right through this pocket. On the pass side, I used the later manifold but probably didn't have to- but I did have to make a small notch in the upper control arm mount/framework. It is possible that the later manifolds do not flow as well though. I used all of the V-6 accessories and that swap was relatively easy, but mine also ran hot. A custom fan shroud that makes the fan pull only through the radiator helps dramatically on any V8 H-body. That along with an electric pusher fan in front keeps the one I have now ('78 327 Monza-13.10@108) cool enough to abuse in anything up to about 95 degrees.
