GT40P headed 306
 

I'm screwing together a GT40P headed 306 so we can put it in my brothers 86 four banger.

I've got a few questions about the heads.

They are unported P heads with the stock valve size. I'm using Manley SS race flow valves but i'm not sure about what type of valve job needs to be done? I've heard that a 3 angle valve job might actually hurt low-lift flow?

Anyways here is the combo

Holley 670 CFM Avenger carb
Edelbrock Air Gap RPM
GT40P Heads
Comp Cams Extreme Energy 274 (302 firing order flat tappet cam)
9.5:1 comp
Stock length rods
1-5/8 Long tubes with 2-1/2 X-pipe and bullet mufflers.

The engine is gonna be backed by a C4 and a 3.55 gear

Max that is good planning. It will be just fine. A good valve and a three angle job will do great.

Yeah, we wanted to put something together reasonably cheap with enough power to have some fun.

So far it hasn't been to terribly expensive. Picked up a engine for 100 bucks, and a set of bare new GT40P's for 230 bucks. My brother has a set of chevy wheels he sold for 500.00 so that will cover the rods and he picked up a back-halved RX-7 for free. We figure we can dump the RX-7 for enough easy money to get some good pistons.

I've been pondering the headers though, might make a switch to 1-1/2 long tubes? It sounds crazy, but with the dinky exhaust valve and the theory behind it (hot high velocity gas) 1-1/2 primaries might work pretty well, in any event. we'll see when we get there.

If you need ANY info on the GT40P's, this site might be of some help. It is a very good resource.

http://www.stangpro.com/html/article...les/gt40p1.htm

Ron

Yeah I checked the page out earlier this week, it was a pretty good site, also there is a guy named mouse that had another very informative site.

Anyone ver notice how the exhaust cross sectioned head in that site is missing part of the exhaust wall? Take a look - someone tampered with the picture - you can tell if you look close enough.

1 1/2 long tubes is the wat to go.