Ford 302 SS build

[Jim Caughlin]

Originally Posted by ShipC1970

Happy Sunday all!

Doing a ton of homework and planing for my super stock 1970 mustang. I have a question in reguards to heads. I am a little confused because It shows that the AFR1399 heads are accepted replacements in the technical bulletins however not in the NHRA accepted replacements. Also in the rulebook it’s a little unclear as to if they are ok to use for super stock. Anyone have experience with this? I do have the matching D00E heads and block for the car and a roller 302 that I could use for GT class. Any help is appreciated.

Thanks!
Chris

If you plan to run the AFR head in SS, get your checkbook out, the heads as delivered have too large of valves. You need to remove all of the seats and weld up the head so you can install the smaller seats to match the smaller valves, then report them to match, not a small or inexpensive undertaking.

[Mark Ugrich]

Originally Posted by Jim Caughlin

If you plan to run the AFR head in SS, get your checkbook out, the heads as delivered have too large of valves. You need to remove all of the seats and weld up the head so you can install the smaller seats to match the smaller valves, then report them to match, not a small or inexpensive undertaking.

You can contact AFR and check if they will supply a “ porters casting” I think they rough in the ports and install the valve guides , possibly install the seats but i’m not sure.They did offer a head with the correct seats for the 289 combination, but that stopped a few years ago.

[fordteacherguy]

Originally Posted by Jim Caughlin

If you plan to run the AFR head in SS, get your checkbook out, the heads as delivered have too large of valves. You need to remove all of the seats and weld up the head so you can install the smaller seats to match the smaller valves, then report them to match, not a small or inexpensive undertaking.

The 68 302 iron head HP dropped to 207 hp and could be a great combo. 23 HP less than aluminum!

[Jim Caughlin]

Originally Posted by fordteacherguy

The 68 302 iron head HP dropped to 207 hp and could be a great combo. 23 HP less than aluminum!

Which carb comes on that combo?

[Doug Hoven]

Originally Posted by Jim Caughlin

Which carb comes on that combo?

Depends on whether you call it a Ford or a Mercury 302. If run as a ford, it gets the 450cfm version of the motorcraft 4300 spread bore, air valve secondary carb. If called a Mercury, you are allowed to run a 600cfm 4150 holley.

[ShipC1970]

Originally Posted by Doug Hoven

Depends on whether you call it a Ford or a Mercury 302. If run as a ford, it gets the 450cfm version of the motorcraft 4300 spread bore, air valve secondary carb. If called a Mercury, you are allowed to run a 600cfm 4150 holley.

Why is that and how is that? So I have the original 70 block and matching heads. So hypothetically even though it’s from a ford mustang and I run it in my mustang in GT/QA or PA and say it’s a “mercury” engine I could run a 4150? Who checks this by the way? Forgive me for all the questions I’m new!

[Jim Caughlin]

Originally Posted by ShipC1970

Why is that and how is that? So I have the original 70 block and matching heads. So hypothetically even though it’s from a ford mustang and I run it in my mustang in GT/QA or PA and say it’s a “mercury” engine I could run a 4150? Who checks this by the way? Forgive me for all the questions I’m new!

You can run GT only if the comb is a hybrid. If the combo can legally be run in SS, you can't run GT. In my case, I am building a '64 Comet with the 289/210 combo. If I run the large Autolite Merc combo, it is a SS/MA. If I run the small Autolite Ford combo, it is a GT/QA. You can't swap between classes, the argument for this rule was that people were running GT with legal SS combos to avoid a potentially losing heads up runs.

[ShipC1970]

Originally Posted by Jim Caughlin

You can run GT only if the comb is a hybrid. If the combo can legally be run in SS, you can't run GT. In my case, I am building a '64 Comet with the 289/210 combo. If I run the large Autolite Merc combo, it is a SS/MA. If I run the small Autolite Ford combo, it is a GT/QA. You can't swap between classes, the argument for this rule was that people were running GT with legal SS combos to avoid a potentially losing heads up runs.

So I have a 89 roller 302 in the garage. If I run that block with a set of 68 302 heads I could run it in GT because it would be a hybrid? And I could claim it as the merc 68 302/220 combo with the 4150?

[Doug Hoven]

Originally Posted by ShipC1970

Why is that and how is that? So I have the original 70 block and matching heads. So hypothetically even though it’s from a ford mustang and I run it in my mustang in GT/QA or PA and say it’s a “mercury” engine I could run a 4150? Who checks this by the way? Forgive me for all the questions I’m new!

No worries, it's confusing to everyone. In "GT" you are allowed to run any engine combination from the "family." For example a 283 in a 4th gen F body, or a pontiac/olds/buick 455 in a camaro. To run a 68 302, you could use your block, but you'd have to find a set of heads for the 68 4bbl engine. Whether it's true or not, the paperwork exists that a Mercury 302 in 1968 was available with a Holley, whereas the Ford cars had the 4300 autolite. So, long story short, to answer your question, yes. You could run a 1968 4bbl 302 with a 4150 in your 1970 mustang in GT/QA or GT/PA.

[Chris1529]

I had a 95 F150 with the 351W that I used to tow with. I think it was only rated at 210 HP then with EFI and was a non roller cam as well. It had 325# torque, but at 2800 rpm. It was a really good engine in that truck as far as pulling with a 1/2 ton 4x4. The Lightning trucks of the day had the GT40 heads I think, but I never drove one for comparison.
I also have the parts for a 69 290HP 351W, but feel its too high a factor to start out with in S/SS unless you really want to do it.