URLACHER54

ok i got a used set of GT40 heads that were rebuilt and have about 2000 miles on them, but the guy i got them from said i probably cant use the springs he has on there that they might be to high.so my question is what do i need to make these bolt on my car with no notching of the pistons or anything like that. what is the max spring size, what roller rockers (1.6 or 1.7) and what cam E303, X303, B303 etc. i do know i will be using the 93 Cobra intake and i have the heads and they have the studs for the rockers but i dont know what or how to change the springs too.

dimebag

springs are decided by the cam... as for the rockers... 1.6 or 1.7 again depending on the lift the cam has, and the lift you want

nitrous_bob

yeah stronger springs for more lift are fine, but you can cause undue stress on the rest of the parts if it's too much.

you need to take them to a shop, they can test them for adequacy, as far as being too physically tall ? what did they come off of ? you can get taller valve covers, and you can remove the oil baffle if thats the only problem. if you use taller valve covers though, make sure your upper will still clear them or you'll need a spacer there.

and like stated, you need to know a rough cam profile. if your using something like a "b" cam, 1.7 is ok as long as the heads are not decked too too much.

mjr46

well if you gotta pass the sniffer here in MD than an e-cam is the safe bet...if not go with an f-cam and match the springs to your cam choice

URLACHER54

by sniffer do you mean emmissions, if so i dont have to go through emmissions because i have historic tags on it

URLACHER54

about how much HP should i get out of these GT40s

URLACHER54

mjr46 where are you in MD

mjr46

historic tags???[sm=WTFsgign.gif]what year stang??? cause to have them the car has to be 25 years old.......I work in frederick where is gambrills?? like near gambrill state park??

URLACHER54

nope, it only has to be 20 years old, and then when i was running the wifes mini van through the emmisions the otherday i asked the manager there, what are the exemptions for emissions and he said historic tags, hot rod tags or 25 years old. but to get historic tags it just needs to be 20 years old. i bought my 88 GT last sprirg and keep the old owners tags on it untilthe2nd of janurary so i could get the historics.Gambrills is near Bowie, MD and about 20 mins from Bmore

nitrous_bob

right out of the box don't expect too much, maby 25 more hp

BUT , they have some great potential.

a little port work goes a long way w/ these heads. you can just about double it by porting the exhaust, cleaning up the intakes, maybe a slight decking since it's not a DD and you can use the increased compression, smooth out the bump and maybe port match the intake to them and also the headers to them

then i think you'd see 50