GT40 heads
03-09-2007, 07:17 PM
#11
2nd Gear Member
Join Date: Nov 2006
Location:
Posts: 171
RE: GT40 heads
As far as getting the gt40p heads you will need to get a different set of headers specially made for those heads. I have tried the small boot thing and it doesn't work. It sits right on the header.
03-10-2007, 03:33 AM
#13
5th Gear Member
Join Date: Nov 2004
Location: Texas
Posts: 3,834
RE: GT40 heads
They are both pretty similar....The GT40's have thermactor bumps which hinder performance some, but they have larger exhaust valves [1.54 compared to the P's 1.46, IIRC]. In stock form, the P's outflow the GT40's up to .500 lift, but the GT40's flow more after that, partly due to their larger exhaust valves.
If you have either ported, they will be very similar except the compression differences. Thumper upgrades the valves to 1.90/1.60 so they will both flow very well. Some say that they will flow w/ aftermarket aluminum heads, but I've never seen dyno charts to prove that.....
If you have either ported, they will be very similar except the compression differences. Thumper upgrades the valves to 1.90/1.60 so they will both flow very well. Some say that they will flow w/ aftermarket aluminum heads, but I've never seen dyno charts to prove that.....
03-10-2007, 07:24 PM
#14
2nd Gear Member
Join Date: Jan 2006
Location:
Posts: 324
RE: GT40 heads
i cant find any gt40 heads in NJ.....i called everywhere and i went to all the junkyards....i found two 96 explorer with full motors and they wont sell em unless i pay 650 for each...b/s dont u think?
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