[66Mustang2021]

Ok I have a 66 mustang coupe with a ATK 302 Crate Motor rated at 250hp at Crank, 325 torque. Has now 600 cfm holly carb, Weiand dual plane intake, stock cam, stock CI heads. Shorty 1 5/8" headers
(soon to be full 2-1/2" exhaust) 4 speed manual trans, 3.23 tru trac rear end.

I just bought and will be installing soon AFR 165CC heads -1399, and Comp Cam Camshaft, Hydraulic Roller Tappet, Advertised Duration 264/270, Lift .544/.544. New roller tip rockers, lifters, etc. Will probably if needed change jets on carb also.

Any guess on what I will be putting down at rwhp with new set up?

TIA

 

[Woodchuck]

Ok I have a 66 mustang coupe with a ATK 302 Crate Motor rated at 250hp at Crank, 325 torque. Has now 600 cfm holly carb, Weiand dual plane intake, stock cam, stock CI heads. Shorty 1 5/8" headers
(soon to be full 2-1/2" exhaust) 4 speed manual trans, 3.23 tru trac rear end.

I just bought and will be installing soon AFR 165CC heads -1399, and Comp Cam Camshaft, Hydraulic Roller Tappet, Advertised Duration 264/270, Lift .544/.544. New roller tip rockers, lifters, etc. Will probably if needed change jets on carb also.

Any guess on what I will be putting down at rwhp with new set up?

TIA

Nope. Not without knowing what they used for pistons and what you're using for head gaskets (compressed thickness) and block deck height, for a start. What does it really matter, anyhow, except for "bragging rights"? What matters is if you like how it drives...

 

[Westmus]

Pure guess 275 hp, based on the usual results people get from the TFS Stage 1 top end kit on a 5.0 in a fox. Similar head flow and a one step bigger cam seems usually to measure like 290 on the wheels. Which fit pretty good with it being sold as a 350hp kit.

 

[Desert66]

AFR 165 heads, rollers, comp cam and Weiand intake made my car run completely different/better. You're going to be smiling ear to ear and that's better than numbers on paper. Good luck with the install. (I'd guess 75 to 80hp crank gain if I had to)

 

[66Mustang2021]

Nope. Not without knowing what they used for pistons and what you're using for head gaskets (compressed thickness) and block deck height, for a start. What does it really matter, anyhow, except for "bragging rights"? What matters is if you like how it drives...

Has nothing to do with bragging rights, just looking for opinion from others who have done similar so I can compare to whatI think I should be at. Head gasket using is Fel Pro 8548PT2 (.047 compressed) . Heads are stock OE thanks

 

[66Mustang2021]

AFR 165 heads, rollers, comp cam and Weiand intake made my car run completely different/better. You're going to be smiling ear to ear and that's better than numbers on paper. Good luck with the install. (I'd guess 75 to 80hp crank gain if I had to)

Cool I am hoping to get at least that much gain. Im looking forward to seeing the difference in power. My car is not intended to be a race car by any means. Just a toy to play with on weekends should make a pretty good difference. Thank for the reply.

 

[Grimbrand]

Has nothing to do with bragging rights, just looking for opinion from others who have done similar so I can compare to whatI think I should be at. Head gasket using is Fel Pro 8548PT2 (.047 compressed) . Heads are stock OE thanks

Those head gaskets are too thick unless your pistons are hanging out of the holes a bit. Usually you want you piston-to-valve clearance to be somewhere between .037-.045 so that you have effective quench. More than .060 puts you in a very scary range that actively causes detonation, but long before that, you lose most of the benefits from running proper clearances.

 

[66Mustang2021]

Those head gaskets are too thick unless your pistons are hanging out of the holes a bit. Usually you want you piston-to-valve clearance to be somewhere between .037-.045 so that you have effective quench. More than .060 puts you in a very scary range that actively causes detonation, but long before that, you lose most of the benefits from running proper clearances.

Thanks when i ordered did not double check the thickness on the head gaskets in kit. Will look into that!

 

[66Mustang2021]

Thanks when i ordered did not double check the thickness on the head gaskets in kit. Will look into that!

Just switched to .039 on head gaskets

 

[DrStang]

I'd say 275hp or so at the rear wheels. Your setup was similar to what I had many years ago and that's what mine was on the Mustang dyno.

 

[awhtx]

You still haven't told us what pistons are in the engine and what the deck height is. What is the difference in combustion chamber CCs between stock heads and AFR heads? You could end up with a compression ratio of 7:1 if you don't pay attention to details.

 

[Helmantel]

Those head gaskets are too thick unless your pistons are hanging out of the holes a bit. Usually you want you piston-to-valve clearance to be somewhere between .037-.045 so that you have effective quench. More than .060 puts you in a very scary range that actively causes detonation, but long before that, you lose most of the benefits from running proper clearances.

I'm sure you meant the piston to squish surface clearance (top of the piston to the flat part of the combustion chamber). Piston to valve clearance should be a little larger.

 

[blkfrd]

Ok I have a 66 mustang coupe with a ATK 302 Crate Motor rated at 250hp at Crank, 325 torque. Has now 600 cfm holly carb, Weiand dual plane intake, stock cam, stock CI heads. Shorty 1 5/8" headers
(soon to be full 2-1/2" exhaust) 4 speed manual trans, 3.23 tru trac rear end.

I just bought and will be installing soon AFR 165CC heads -1399, and Comp Cam Camshaft, Hydraulic Roller Tappet, Advertised Duration 264/270, Lift .544/.544. New roller tip rockers, lifters, etc. Will probably if needed change jets on carb also.

Any guess on what I will be putting down at rwhp with new set up?

TIA

This sounds almost exactly like what I helped JeffinOC with. He started with an almost new 245HP 302 from Blueprint. Same everything except your cam is a step up. You need to determine how much in or out of the hole your pistons are. Then you can determine what head gasket to use. In Jeff's case, his pistons were .020 in the hole and we used a .027 Cometic head gasket. Decent .047 quench. Low .040s might have been better but no head gasket thinner than .027 was available except copper which was not appropriate for his engine.

mid to high 300s in terms of HP at the flywheel assuming 600 or 650 cfm carb. Try to open up your shorty header flange to match the AFR exhaust port. Otherwise it is probably smaller and will restrict exhaust flow. Better yet, long tubes.

 

[66Mustang2021]

You still haven't told us what pistons are in the engine and what the deck height is. What is the difference in combustion chamber CCs between stock heads and AFR heads? You could end up with a compression ratio of 7:1 if you don't pay attention to details.

Sorry dont have alot of info on existing motor. I dont know what the pistons are, wont know til i tear it apart. only info i have on them is they are Hypereutectic. Same with deck height. heads are OE Cast iron all I know. Has a flat tappet cam. 8.5:1 compression as it sits. Rocker arms 1.5 ratio going to 1.7, existing bore and stroke 4.060"x 3.000" Stock motor pretty much.

 

[66Mustang2021]

This sounds almost exactly like what I helped JeffinOC with. He started with an almost new 245HP 302 from Blueprint. Same everything except your cam is a step up. You need to determine how much in or out of the hole your pistons are. Then you can determine what head gasket to use. In Jeff's case, his pistons were .020 in the hole and we used a .027 Cometic head gasket. Decent .047 quench. Low .040s might have been better but no head gasket thinner than .027 was available except copper which was not appropriate for his engine.

mid to high 300s in terms of HP at the flywheel assuming 600 or 650 cfm carb. Try to open up your shorty header flange to match the AFR exhaust port. Otherwise it is probably smaller and will restrict exhaust flow. Better yet, long tubes.

thanks! yeah I figured that on the pistons, as I mentioned in other reply dont have much info on existing motor, wont know really until I pull it and see what I have. That kind of HP is what I was thinking, actually that is little better than what I thought. I was thinking/hoping for 340-350 at flywheel when i am all done.

 

[66Mustang2021]

Sorry dont have alot of info on existing motor. I dont know what the pistons are, wont know til i tear it apart. only info i have on them is they are Hypereutectic. Same with deck height. heads are OE Cast iron all I know. Has a flat tappet cam. 8.5:1 compression as it sits. Rocker arms 1.5 ratio going to 1.7, existing bore and stroke 4.060"x 3.000" Stock motor pretty much.

Looking at a newer sheet on the pretty much same engine at Summit looks like the stock heads would be around 62cc. So based upon that and the afr 165's I would actually calculate out to little over 9:1 compression.

 

[HoosierBuddy]

When I put those heads on my 289, I went with KB116 "pop up" style pistons, which got me to right at 10:1. I wasn't running as much lift as you are. I never had it on a dyno, but it ran like a scalded dog. I think you'll be pleased.

 

[66Mustang2021]

When I put those heads on my 289, I went with KB116 "pop up" style pistons, which got me to right at 10:1. I wasn't running as much lift as you are. I never had it on a dyno, but it ran like a scalded dog. I think you'll be pleased.

thanks! at this point not planning on changing pistons but never know what happens once i get motor opened up lol.

 

[G's 70]

Do you already have the heads? Trick Flow has heads with 53cc chambers.

 

[Woodchuck]

a. Send the head gaskets back. Pull the head(s), put a straight-edge across the top of a cylinder and use a feeler-gauge to estimate deck clearance. If you can grab a dial indicator with a magnetic base use that instead. Once you've determined your deck clearance, THEN order your head gaskets, shooting for a quench distance of .038-.042" (or as close as you can get).

b. Stock Ford rocker ratio is 1.6:1, not 1.5:1. There's no reason to go with 1.7:1, especially on the intake side... just get a camshaft with more exhaust duration instead. While we're on the subject of camshafts, IMHO the one you selected has too much lift. If I was going to pick a decent "street" cam in a "roller", from Comp, I'd probably choose a 35-351-8... but that's just me. For our 289 build we chose a M-6250-E303 for a bit more bottom end torque and fuel mileage... especially running 3.70's and a 1:1 high gear.

c. Stick with the AFR's... the difference between 53 and 58cc is going to be about .5 in static compression but static compression is only part of the overall picture.

One final, and oft-repeated (by me, anyhow) bit of advice from an "Old Fart" who was, believe it or not, young and inexperienced at one time long, long ago in a galaxy far, far away.....

Websites and catalogs are GREAT! However, they are, for all intents and purposes, advertising for stuff that vendors/manufacturers, etc., want you to BUY. Selecting the right COMBINATION of parts should be the goal, not the ones that, individually, promise to be the next best thing since sliced bread. One of those things that these sellers use is what I call the "Psychology of Horsepower" that goes hand-in-hand with "Bigger is Better" syndrome... So, think about this for a minute or two. Which engine would you want for a "street cruiser", below...