Old ford heads on fox
- Thread starter lxhatch91
- Start date
-
Sponsors (?)
Although debatable, I think most would agree that the best production iron heads for a 302, that are reasonably priced and attainable are GT40 heads, and they're littered across any junk yard. You can pick them up cheap, lap the valves, put new seals on, and be running on a shoestring budget. If you have a little more time and money to play with, have them decked, put new springs on, and do some minor DIY porting and you'll have a great set of heads for $400 or so.
79 Fox
Active Member
I'd agree. I got a set of GT40P head that already had upgraded valve springs for 200 bucks. I've read that you can get up to 40 horsepower out of these heads on a stock 5.0 HO
I'd agree that any pre GT40 head is an absolute waste of time and money. With zero to be gained over the later head.
79 Fox
Active Member
If you're willing, there is a lot of info sprinkled around the net on how to port GT40 heads. I did a set a while ago. You can do a few small things and make big gains before getting sucked into the minutia for diminishing returns. I think you can spend a goot 15 minutes on each port and get the low hanging fruits. Two important things:
- Dont get greedy
- Don't grind the floor of the port
Rusty67
Dirt-Old 20+Year Member
The answer to your original question is yes you can do that. The push rod motor 289/302/351/5.0/5.8 heads are interchangeable. The big difference is you need to use a larger head bolt on the 351/5.8 heads so you have to tap the block out to accept the larger bolt but this is actually a good thing because it provides you more clamping force with the larger bolt so you don't blow a head gasket. I'm not sure if this is true on the newer 5.0 blocks but on the older blocks they did use a smaller bolt on the head.
As for if the GT40P heads are better, it depends on the head you get. The GT40 head was based on a factory head from I think the 69 351W motor. That was the base design they started with and went from there. I don't remember if it is the 2v head or 4v head but I think it is the 4v head. If you get the right head and port it I think it actually out flows the GT40/P head (even ported) but it has been a while since I've reviewed that info.
If you get a set of GT40P heads just be aware of the spark plug angle, makes changing the plugs a bitch when you have headers on. I'm not sure if he is still doing it because I've been out of the game for a while but Thumper460 used to run a professional porting service and he gave forum members a bit of a discount. Lots of people said he did a great job. If you want to get crazy with modifying the head, you can make a fair amount of power. If you are going to be making 300+ horse pwoer, you should look at swapping the oprange top 19#/hr injectors our for some blue top 24#/hr injectors and get yourself a good tune.
As for if the GT40P heads are better, it depends on the head you get. The GT40 head was based on a factory head from I think the 69 351W motor. That was the base design they started with and went from there. I don't remember if it is the 2v head or 4v head but I think it is the 4v head. If you get the right head and port it I think it actually out flows the GT40/P head (even ported) but it has been a while since I've reviewed that info.
If you get a set of GT40P heads just be aware of the spark plug angle, makes changing the plugs a bitch when you have headers on. I'm not sure if he is still doing it because I've been out of the game for a while but Thumper460 used to run a professional porting service and he gave forum members a bit of a discount. Lots of people said he did a great job. If you want to get crazy with modifying the head, you can make a fair amount of power. If you are going to be making 300+ horse pwoer, you should look at swapping the oprange top 19#/hr injectors our for some blue top 24#/hr injectors and get yourself a good tune.
Thanks for the reply !
I have now the gt40p head ready to swap but im gonna change for gt40 ,
I have long tube bbk 1 5/8 stanless ,
They dont work with gt40p .
Im gonna change the 2 intake for gt40 intanke, they flow very good compare to the stock one . Maybe im gonna get 20hp with the 2 intake only . When i find my new set of head im gonna get more few hp . Lot of fun LOL
I have now the gt40p head ready to swap but im gonna change for gt40 ,
I have long tube bbk 1 5/8 stanless ,
They dont work with gt40p .
Im gonna change the 2 intake for gt40 intanke, they flow very good compare to the stock one . Maybe im gonna get 20hp with the 2 intake only . When i find my new set of head im gonna get more few hp . Lot of fun LOL
Rusty67
Dirt-Old 20+Year Member
Yep, that spark plug angle will get you like that. Good luck with the swap. What cam are you going to run?
