JERM_1967stang

well I was talking to a friend and he said that GT-40 heads would fit on my 1967 289W.
is this true? what would i have to change (lifter, rods, ect.)?? would this be a good upgrade?

69thunder

Everything from the cam up to the head.

67mustang302

Those are pretty much the best budget heads you can get, and hard to find these days. If they're true GT40 heads and you can get them for cheap, I'd go for it. That with a nice hyd roller cam swap into a289 can get you some decent power.

KBunny

Unless you like spending loads of money for something that will only be of great value when you are consistently racing then don't go near the roller lifters it costs allot and it is only utilized if you are running an aggressive cam and high RPM's.

Yes you will get some benefits with a somewhat stock application in reliability and longevity and a few extra HP but I doubt you will even notice the HP increase when you are driving down the road. For people like us who cant stop tinkering with our cars the reliability and longevity is already greatly increased because we take care of them.

my $0.02

But yes if you can get a set of GT 40 heads they will bolt on to the block.

my77stang

most definately worth it. larger and better shaped ports and bigger valves, plus the ex seats are hardened so your not beating the crap out of your motor with unleaded fuel

countryboy116

I'm not positive but isn't there some difference between a GT-40 head and GT-40P head, im sure someone will know in here.

my77stang

spark plug angle is difference between the 40's and the 40P's. the P's are better, but you may have header / spark plug fitment issues. also, the P's have a smaller ex valve and should be upgraded to the regular 40 size ex valves (1.54 instead of 1.46)

67mustang302

If the only advantages for roller cams are in high rpm racing setups, then why did all the auto makers spend the money to switch to them back in the mid-late 80's? Roller cams have huge advantages in economy over a flat tappet, you can have a modest lobe profile to maintain low rpm drivability and good cylinder pressure, but move more air. It's all about volumetric efficiency. Better VE comes out to better power, better mileage, and better drivability. Yeah, roller cams cost money but they are worth the cost.

JERM_1967stang

well that reall didnt answer the question would i be able to just unbolt the old heads and bolt up the new?? or do i have to change anything

69thunder

I did, you need to change out/replace the cam and everything associated with opening the valves. Heres a list: cam, lifters, pushrods, and possibly rocker arms if the heads don't have them. Yes they will just bolt up but what's the point if the valves don't open........