I am 84 YO., and building my last SBC 400 and will be over

[oldhead]

I think this is the guy that has a Holley dp on his car and the secondary’s are controlled by a cruise control unit on something.
He was supposed to post pics, Yes the cruise control is very good, takes a little over one second to open the secondary after the primary is open full Bob Oldhead

[ClassicComp]

Interesting idea, please post some pics

[Kevin Johnson]

Good description here:

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

[enigma57]

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

[rebelrouser]

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

[oldhead]

SORRY NO PICTURES,I don't know how Oldhead

[Caprimaniac]

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.

[Elroy]

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

[econo racer]

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

[dwilliams]

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.