Don Terrill’s Speed-Talk

When I was doing more carb testing years ago, it was when I had a SF-110 bench, so the actual test pressure was 10”, and was converted to 20.4”. I did a couple of tests at different pressures on the CFS carb today. Tested at 20.4”, then 28”, then 10”. The converted numbers are pretty close to the ac...

The SF carb testing adapter comes with a 4 hole spacer that has 1.687” bores. I found one that has 1.750” bores that I use for the carbs that use the 1.750” baseplates. I hadn’t done that test in many years, so I did it again today. On the HP950, using the adapter with the 1.687” bores dropped the d...

HP750- BG750- CFS850

Some pics of the test subjects:
4777- 4779- 4781- HP950-

I didn’t

Some discussion involving carb flow rates for various carb configurations was brought up in Steve Cowan’s 383 dyno thread, and I figured rather than clutter up his thread, I’d start a new one……. Let me start out by saying this is not at all meant to be a definitive set of results, but just a compari...

Steve, I have an old 4781 that I had annular boosters installed along with thinned throttle shafts, choke tower removed, mild Venturi blending, adjustable air bleeds installed, and the fuel curve reworked. I had this done in 1991…….. before there was such a thing as an HP Holley carb. I had it done ...

Using a 4 hole adapter to flow carbs on the bench…… one hole at a time…….. on my bench the original style 1.375 x 1.750 Holley HP950 flows about 860cfm. That’s flowing each hole, adding the numbers together, then multiplying the total by .92 to approximate wet flow. I built mine from a bare Holley ...

Using a 4 hole adapter to flow carbs on the bench…… one hole at a time…….. on my bench the original style 1.375 x 1.750 Holley HP950 flows about 860cfm. That’s flowing each hole, adding the numbers together, then multiplying the total by .92 to approximate wet flow. I built mine from a bare Holley m...

I’m assuming this build is also a 383? I wonder how much different the numbers would be without the inertia correction. Yes 383 cubes. From your experience is there a percentage loss you typically see without IC ? It's same dyno I have used before, same set up etc. Interested in your opinion and th...

I’m assuming this build is also a 383?

I wonder how much different the numbers would be without the inertia correction.

If it’s the 1.460” dual……..I do that all the time.
It’s a PAC-1903……..which is a drop-in replacement for the old Crane 99893 in many applications.
PAC lists it as a HR spring.

I rarely get any Olds heads in the shop, but a couple of years ago I had some 7a heads from a 350 here. I machined the seats and swapped out the valves to 1.99/1.62(both 45*), and blended the bowls to suit. The valves used were just SBI stock replacements. It was one of those”IIWII” situations, but ...

Seems like there was a thread regarding the tool steel lifters and cams wearing out not that long ago over on class racer.

The head I have here looks to be unmolested from the factory. The OD of the 45 angle of the valve job measures 1.91”, and the OE valves I took out are 1.94”. IMG_3394.jpeg IMG_3395.jpeg IMG_3396.jpeg There are also differences in opinion on the claimed chamber volume……76 or 64. This head, which stil...