GT-40X heads ?
 

History:
My son and I are upgrading the top end of our project car H/I/C - we've installed the Typhoon upper/lower intake, X303 cam. Currently money ran out, so couldn't do heads, which we're now paying the performance gods, as we've got lose of power with this setup until we get the heads take care of. My son did the research and decided on AFR185 heads, but we've since found out with this cam/head combo - won't run on stock bottom. Pistons need to be notched.

The AFR-185s are in our long-term plans, as we want to go with a stroker crate motor with those heads. Trying to avoid buying two sets of heads, one for now with stock bottom end, and one with crate motor in the future.

On to my questions:

Can I get opinions on GT-40X heads? These heads are much cheaper then the AFR165s(which will work on stock bottom), Edlebrock, and others.

Any comments on how these heads will flow with the X303 and typhoon combo we have?

In all honesty, look at a set of Trick Flows. They'll answer valve clearnace issues most of the time. Not to mention, they are inexpensive versus almost any aluminum head, and they flow pretty darned good. Comparable to the AFRs. You won't go wrong with them. Either the TW, Street Heats or High Ports will give you more than enough cylinder head, and room to grow.

We looked at Twisted Wedge heads, but I remember we'd have to change our MAC long-tubes.

The AFR 165s will clear with that cam. And give you the power you are looking for.

Agreed, try explaining rational logic to a teenager who is reading higher flow numbers and hp with the AFR185s. Everything I've read about the 165s, they're plenty flowin heads.

My son is starting to think long-term and planning, which we've talked about several times. His thoughts are valid - looking at a stroker crate motor over time, with 185s, and a NOVI2000.

If we can find something cheap to help our pony we'll go that route. If not, I guess we'll look at the 165s for the short term. I think my son will be surprized how well this combo will run, with some additional mods to the suspension and better times.

I'll recommend the TW's. They will work great now out of the box, then when you upgrade to the stroker with the Novi2000, just have them ported. You can easily get 190cc port volume on the intake side.

Flow numbers do not tell the whole story. We recently tried 2 different sets of Tw's and 1 set of ST 5.0's on a friends car and the all had very similiar flow numbers. However 1 set of TW's kicked the crap out of the other 2 heads on the engine dyno. Another thing to look at is flow techniques of the cylinder head companies. AFR flows their heads on a 4.125 bore adaptor with the head centered. Flow a TW like that and they will pick up alot!

Another thing, you should have to change headers to run the TW's. Its the R head that you need to stay away from.

Andy

heads?
 

why did one set of tw's beat the other set of tw's?
Ryan

Re: heads?
 

Why is one stock stang faster than another? Just the way the manufacturing process and tolerances fall out. Also, any other factors that might affect the dyno - different day, weather, etc.

Both of the TW's were prepped differently. Neither of them were in out of the box form. They werent ported at all, but they did have different valves and different valve jobs. The flow numbers were real close, higher at some lift numbers, and lower at others.

Andy

Sorry, thats a misprint. It should say you shouldnt have to change headers to run the standard TW.

Andy