Don Terrill’s Speed-Talk

Interesting idea, please post some pics

Good description here:

https://www.theturboforums.com/threads/vacuum-secondary-holley-carb-question.328338/#post-1385440 wrote:Boy Tom that a mouthful ....In my Malibu I come of the line at idle(650rpm) I have a mech.open 950,I was getting a bog,so I installed a modified cruise control,hooked it to the vacuum can that I use for the power brakes and used a peice of linkage hooking the cruise to the secondary.....Have a micro switch on the primarys that opens the secondary when primary reachs full open.....now 1.28 and 1.30s with a very tight convertor.The secondarys open slowly(takes 2 seconds)...I love it...Works great... OLDHEAD

An interesting idea indeed! Would appreciate any pics or further info. We will be running an annular booster 600 CFM Autolite carb original to a '58 Mercury Marauder 383 engine on son's 350 Chevy (road car). It would be fun to experiment with a similar mechanism for opening the secondaries on our carb.

Best regards,

Harry

Years ago, racing in the no box class, I set up a throttle controller using an air cylinder similar to the link. I had two line locks one for front and one for the back brakes. I had a small air tank in the car and I kept it pressurized with a sears 12 volt tire compressor between rounds. I had it set that when I energized the line locks, the air was exhausted from the cylinder and the throttle would only open to my preset line launch rpm. When I released the button the line locks released and the air cylinder opened the throttle. The other benefit was I could adjust the speed of the throttle opening with a orifice in the line from the air bottle, so on slick tracks it would help keep the tires from spinning. Also the drivetrain was under load so the shock of a transbrake was eliminated as well. It really worked great, won a lot of races. A similar system off a throttle switch could easily operate the secondaries. Racing NSS now, no longer legal to run.


https://www.jegs.com/p/K-R/K-R-Performa ... 6/10002/-1

SORRY NO PICTURES,I don't know how Oldhead

Cool, Oldhead!

Click "Attachments" under the bottom of the white screen- area where you add text. Add Your files (Pictures) from yur PC.

Very mucho good Luck With you "last" build.

Fantastic to be thinking and doing it at 84 years. Much less that much horsepower. I hope I can be in a similar situation, not too far behind you in seniority

What track will you try it at. Love to see it

I've listened to all the exposition about bearing speed, oil heating, frictional losses, yadda yadda, but I've also taken apart a lot of 400 cores and never noticed any unusual main bearing issues, and I freshened up many 400 and 375 dirt track motors back when useable factory blocks were still a thing. Other than the usual distress from poor tuning and refusal to run air filters I never noticed anything unusual there, either.

I can accept that things might be much different for an engine running a 500 mile NASCAR race, but unless you're planning to do that, one is as good as the other.