Horsepower numbers

[D.Hearne]

Ok, so I am confused now. I have been doing some research myself and here is what I have found. The cast iron heads that were on my motor are 69 castings. I found this casting number on a website for Ford engine parts and it shows them to be 63cc heads. ?

The only book I have lists one 69 302 head----C9TE and it's listed as having a 58 cc chamber

 

[sapphire shelby]

You have to take into account the different piston pin heights used over the years. Here's the numbers I used for yours: 64 cc heads, 9 ccs for the gasket, 5 cc's for the valve reliefs and area around the piston to wall down to the top ring. That works out to a 9 to 1 ratio.





The heads that I am getting are not 64cc heads like you keep figuring into your formula. The heads I am getting are 61cc heads.

Also, the casting on my heads is not the C9TE heads. Those are the truck heads. Mine are the C80E heads and are listed as 63cc heads.

 

[D.Hearne]

You have to take into account the different piston pin heights used over the years. Here's the numbers I used for yours: 64 cc heads, 9 ccs for the gasket, 5 cc's for the valve reliefs and area around the piston to wall down to the top ring. That works out to a 9 to 1 ratio.





The heads that I am getting are not 64cc heads like you keep figuring into your formula. The heads I am getting are 61cc heads.

Also, the casting on my heads is not the C9TE heads. Those are the truck heads. Mine are the C80E heads and are listed as 63cc heads.

You posted previously that you had 69 castings, hence they would be C9TE's. As for the 3 cc difference, do the math to correct it. I'm only trying to help you avoid a mistake in running the wrong compression ratio with the cam you've chosen. If you're not happy with that, then do the math and homework yourself. I'm done here.

 

[htwheelz67]

I would be almost positive that you will have to fly cut the pistons with that cam and TW heads.

 

[rbohm]

Hello all,

I am trying to get an idea of some horsepower numbers. There is not a dyno locally so I figured this would be just as good. I know it will not be exact but like I said, I am just trying to get a better idea of the numbers. Here is my set up:

306 cubic inch with flat top pistons

Twisted Wedge street/strip heads with 2.02/1.60 valves and 61cc combustion chambers

Comp Cams solid lifter cam with 576 intake/ 570 exhaust lift and 255 intake/ 266 exhaust duration @.050

Cobra dual plane high rise intake

Holley 715 Shelby carb

Tri-Y headers

I mostly run this car on the street with several trips a year to the drag strip. I know the cam is a little much, but since I got the new cam and lifters for free I wasn't going to turn them down. Besides it helps me on the big end at the track. I ran this set up with the stock cast iron heads for over a year and am getting ready to put on the aluminum heads as soon as they come in. I am thinking around 325-350 at the flywheel. Is that being too generous? What does everyone else think?

Thanks for the input.

350-375hp is quite doable with this combination depending on your tuning skills. some thoughts though;

1: you have much larger valves than the stock heads have so you will have to flycut the pistons for clearance.

2: the twisted wedge heads put the valves in different locations over the pistons, so if you take the pistons to be flycut, make sure the shop that does the work knows in no uncertain terms where the flycutting needs to be. or you can get the needed tool from comp cams and flycut your own pistons.