Don Terrill’s Speed-Talk

I was given a very simple job on these heads. Have them beat a cnc head! I figured I could pull 310cfm/210cfm with a 215-220cc port. I am beating my brains out and making no gains at this point. Lots of cut and flow test. I am probably missing something simple. I have never done a set of these before. I do not like the ssr at all, seems too far down the intake port. Stock these are a decent street head with radiused seats and good flow for .5" cam. Any help is welcome thanks, Charlie

2.08/1.6 valves 38/45/60/75 intake seat 30/45/60/75 exhaust seat. 224cc intake port and 82 cc exhaust port. 317ft/sec pinch, 375.6ft/sec center of ssr and 364 ft/sec toward the center of cylinder ssr.

D.V. flowbench program. Lots of info and I may not have it all filled out perfect. If you see a mistake please let me know. The efficiency of these ports are not great, still using a 1204 opening.Thanks, Charlie

Stupid amount of work on this ssr and the speed is still high across it. Finally below 400ft/sec. Stock ssr is very laid back and high. Thanks, Charlie

Without fibbing, that's about all that head will do as far as a number.

Once again, someone is hung up on flow numbers. You can flow 290 and find power without the port never going up from 290. It's not all about the flow number.

I know flow numbers are just a piece of the equation. The swirl is pretty good on these 3236 rpm @ .8" lift and the air speeds are ok. Am I missing something? Thanks, Charlie

I should include that the chamber is cut for 350 style felpro head gasket. Thanks, Charlie

Carnut1 wrote:

1222161940_HDR.jpg

D.V. flowbench program. Lots of info and I may not have it all filled out perfect. If you see a mistake please let me know. The efficiency of these ports are not great, still using a 1204 opening.Thanks, Charlie

Is that the new flow bench program that David gave you as part of the new seminar?

Did you measure the CSA throughout the runner? How is it sized?

I remember Chad Spiere stating that the 200cc PRO 1'S had a lot of meat for shaping. Would anything be gained by opening the gasket side up to a 1205 gasket and shaping it up to the pinch point and opening it up appropriately? or do you think the airspeed will fall off too much? As some of the offshore heads that flow really well already have a 1205 port opening's

Excuse the lame question I fall short on the porting Knowledge although I am learning daily from my current teacher.

jcisworthy wrote:Did you measure the CSA throughout the runner? How is it sized?

Pinch was 2.354 " - radius. The ssr is 3.026" - radius. Thanks, Charlie

gvx wrote:I remember Chad Spiere stating that the 200cc PRO 1'S had a lot of meat for shaping. Would anything be gained by opening the gasket side up to a 1205 gasket and shaping it up to the pinch point and opening it up appropriately? or do you think the airspeed will fall off too much? As some of the offshore heads that flow really well already have a 1205 port opening's

Excuse the lame question I fall short on the porting Knowledge although I am learning daily from my current teacher.

The airspeed through the pinch now is 317 ft/sec and I was hoping for some input before cutting them for a bigger gasket size. Thanks, Charlie

gvx wrote:

Carnut1 wrote:

1222161940_HDR.jpg

D.V. flowbench program. Lots of info and I may not have it all filled out perfect. If you see a mistake please let me know. The efficiency of these ports are not great, still using a 1204 opening.Thanks, Charlie

Is that the new flow bench program that David gave you as part of the new seminar?

The program is still being finalized but has lots of great features. Yes.

Those heads will flow 330s without welding. The port ends up in the high 230s though. Your best to figure out how big you want them before you worry about flow numbers.

Its funny......I literally (tuesday) just got through roughing in some dart pro 1 200's, with a 2.02 valve. I scribbled down the flow from the first, and second trip to the bench.......