Don Terrill’s Speed-Talk

I’ve never really ran it hopped up but it runs 10:70 123.74 in normal bracket race mode I’ve only had 2 heads up in 10 years.I just want some to know you don’t have to go to extreme to get a cleveland to run far under the index.I believe that’s why it’s not a lot of cleveland stocker racer because they might believe something that may not be true and thousands of chevy stocker small blocks.

Thanks for sharing. I want to do a pump gas oc head setup. I dont think 550 or 600 is out of reach. I did a 9.3:1 oc that hit 468@ 6000 owner didn’t want to rev past 6000 i had stan weiss map the power curve at it went 503@6700. Technically. Lol

Our own little 3000lb mustang runs 6.85 in 1/8 at 99-100. 357 cubes c4 and shift at 7300. I did the above seat trick to these heads also but added porting also. These heads flowed 368@.600 lift. With a .657 flat tappet and 850 carb on top strip dommy intake. If my bottom end was a little beefier we would cam it more and spin harder. Likely wake right up

fordified wrote: ↑Tue Nov 10, 2020 11:24 am

Steve.k wrote: ↑Tue Nov 10, 2020 11:15 am Are you guys doing anything special to blocks? What kind od hp you seeing? Must be close to 650-700

Aftermarket block and good steel crank. No billets.

So windsor block.

fordified wrote: ↑Tue Nov 10, 2020 10:29 am Here's a set of heads that we've been working on. They flow almost 370 at .800.

I've included a picture of the ports compared to a yates heads with a lot of work done. The Yates heads have smaller ports and flow 390 CFM at .800 with a 2.150 valve

What do you mean by "smaller"? Smaller than what and where? The port opening? Pinch? Turn? Bowl? The average csa is what really matters.

treyrags wrote: ↑Wed Nov 11, 2020 6:33 am

fordified wrote: ↑Tue Nov 10, 2020 10:29 am Here's a set of heads that we've been working on. They flow almost 370 at .800.

I've included a picture of the ports compared to a yates heads with a lot of work done. The Yates heads have smaller ports and flow 390 CFM at .800 with a 2.150 valve

What do you mean by "smaller"? Smaller than what and where? The port opening? Pinch? Turn? Bowl? The average csa is what really matters.

Treyrags you do alot of Clevelands do you guys fill or mostly just port?

Steve.k wrote: ↑Wed Nov 11, 2020 9:55 am

treyrags wrote: ↑Wed Nov 11, 2020 6:33 am

fordified wrote: ↑Tue Nov 10, 2020 10:29 am Here's a set of heads that we've been working on. They flow almost 370 at .800.

I've included a picture of the ports compared to a yates heads with a lot of work done. The Yates heads have smaller ports and flow 390 CFM at .800 with a 2.150 valve

What do you mean by "smaller"? Smaller than what and where? The port opening? Pinch? Turn? Bowl? The average csa is what really matters.

Treyrags you do alot of Clevelands do you guys fill or mostly just port?


Haven't messed with Cleveland heads in many years, but both fill and port. These images are from a 311 inch Boss we ran in comp way back. Peak ~ 9500, shift ~ 9800.

treyrags wrote: ↑Wed Nov 11, 2020 10:38 am

Steve.k wrote: ↑Wed Nov 11, 2020 9:55 am

treyrags wrote: ↑Wed Nov 11, 2020 6:33 am
What do you mean by "smaller"? Smaller than what and where? The port opening? Pinch? Turn? Bowl? The average csa is what really matters.

Treyrags you do alot of Clevelands do you guys fill or mostly just port?


Haven't messed with Cleveland heads in many years, but both fill and port. These images are from a 311 inch Boss we ran in comp way back. Peak ~ 9500, shift ~ 9800.

Ahh yes. Straighten shot on a3.what about standard iron? And is there a specific minimum square inch you like to be.

Steve there really is no set area for any head. The area is dictated in each situation by the target peak HP rpm and engine displacement. These heads would be a turd if they were going on the same size engine set up to peak at 8000.

treyrags wrote: ↑Wed Nov 11, 2020 12:21 pm Steve there really is no set area for any head. The area is dictated in each situation by the target peak HP rpm and engine displacement. These heads would be a turd if they were going on the same size engine set up to peak at 8000.

What would you recommend for a street/strip 393 Cleveland with 4v closed chamber heads shifting at 6500 rpm? How do you know how big to make the port area? Thanks.

I would suggest learning the basics by reading publications like "practical engine airflow". Once you get comfortable with the fundamentals then I would suggest buying and learning how to use Larry Meaux's PipeMax program. Larry has dedicated most of his life to induction and exhaust testing and is referenced many times in the above mentioned book. If you don't feel comfortable with doing the porting yourself then I would suggest someone like Chad who does it professionally

Steve.k wrote: ↑Tue Nov 10, 2020 11:01 am 8BFF3EA3-8346-4CC3-A931-1C2177DA4C32.png
Here is stock E chamber. That’s interesting. Im not sure what class original poster is in.I guess it depends where he wants to go. A quick port job will pick him up a fair bit.

If someone wouldn't mind sharing some info here, I'm thinking about doing seats like this. These look like the copper style seats, I was just going to try installing iron. I have the heads in my possession now and after seeing the factory valve job with that undercut under the 45, I understand now why this is so important. What ID/OD and depth seat inserts would I want to install?

cgarb wrote: ↑Wed Nov 11, 2020 6:07 pm

Steve.k wrote: ↑Tue Nov 10, 2020 11:01 am 8BFF3EA3-8346-4CC3-A931-1C2177DA4C32.png
Here is stock E chamber. That’s interesting. Im not sure what class original poster is in.I guess it depends where he wants to go. A quick port job will pick him up a fair bit.

If someone wouldn't mind sharing some info here, I'm thinking about doing seats like this. These look like the copper style seats, I was just going to try installing iron. I have the heads in my possession now and after seeing the factory valve job with that undercut under the 45, I understand now why this is so important. What ID/OD and depth seat inserts would I want to install?

That is the million dollar question right there.

Steve.k wrote: ↑Thu Nov 12, 2020 2:03 am

cgarb wrote: ↑Wed Nov 11, 2020 6:07 pm

Steve.k wrote: ↑Tue Nov 10, 2020 11:01 am 8BFF3EA3-8346-4CC3-A931-1C2177DA4C32.png
Here is stock E chamber. That’s interesting. Im not sure what class original poster is in.I guess it depends where he wants to go. A quick port job will pick him up a fair bit.

If someone wouldn't mind sharing some info here, I'm thinking about doing seats like this. These look like the copper style seats, I was just going to try installing iron. I have the heads in my possession now and after seeing the factory valve job with that undercut under the 45, I understand now why this is so important. What ID/OD and depth seat inserts would I want to install?

That is the million dollar question right there.

That's fine, I'll figure it out. Thanks for the pointer though.

Pm sent