Holley-which secondary spring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

johnwaynejeep · 07-20-2017, 12:07 AM

I'm replacing my QJet with a Holley 4160 (1850-2). I need help in choosing the correct spring for the vacuum secondary diaphragm to make sure they open at the right time. I have a 75 C10 short bed flare side. The title says the weight is 3050. I think the real weight is more like 3750.

Is there a chart to cross reference vehicle weight with the diaphragm spring?

Thanks
Robert

BTW, I've had great luck with the Qjet and I plan to rebuild the Qjet and have it on the backburner ready to install.

geezer#99 · 07-20-2017, 09:07 AM

THe tried and true method is your 'buttometer'!!
Go one step at a time weaker on the springs until you get a bog then go back one spring.
Btw your truck likely is pushing closer to 4200 lbs.

johnwaynejeep · 07-20-2017, 12:37 PM

sounds good. thanks

Titomars · 07-20-2017, 03:22 PM

Assuming you have a S/B and it is fairly stock try starting with the long yellow spring. You will probably find that to be the best overall. My 75 El Camino with a 350 likes that spring best. I am running an 1850-1. secondary spring tuning is based on WOT, rpm range, car weight and gears.

07-20-2017, 12:07 AM	#1
johnwaynejeep Registered User Join Date: Jul 2014 Location: Pacific Grove, CA Posts: 105	Holley-which secondary spring I'm replacing my QJet with a Holley 4160 (1850-2). I need help in choosing the correct spring for the vacuum secondary diaphragm to make sure they open at the right time. I have a 75 C10 short bed flare side. The title says the weight is 3050. I think the real weight is more like 3750. Is there a chart to cross reference vehicle weight with the diaphragm spring? Thanks Robert BTW, I've had great luck with the Qjet and I plan to rebuild the Qjet and have it on the backburner ready to install. __________________ Robert 1975 C10 - Huckleberry 2007 Jeep JK - John Wayne Jeep Smittybilt front/rear bumper, 10K winch Pacific Grove, CA

07-20-2017, 09:07 AM	#2
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,733	Re: Holley-which secondary spring THe tried and true method is your 'buttometer'!! Go one step at a time weaker on the springs until you get a bog then go back one spring. Btw your truck likely is pushing closer to 4200 lbs.

07-20-2017, 12:37 PM	#3
johnwaynejeep Registered User Join Date: Jul 2014 Location: Pacific Grove, CA Posts: 105	Re: Holley-which secondary spring sounds good. thanks __________________ Robert 1975 C10 - Huckleberry 2007 Jeep JK - John Wayne Jeep Smittybilt front/rear bumper, 10K winch Pacific Grove, CA

07-20-2017, 03:22 PM	#4
Titomars Registered User Join Date: Feb 2015 Location: Santa Rosa, Ca. Posts: 539	Re: Holley-which secondary spring Assuming you have a S/B and it is fairly stock try starting with the long yellow spring. You will probably find that to be the best overall. My 75 El Camino with a 350 likes that spring best. I am running an 1850-1. secondary spring tuning is based on WOT, rpm range, car weight and gears. __________________ 1977 Chevrolet C/10 Silverado. Step-Side, Factory 454, TH400, 3.73 Posi 12 Bolt. 1975 Chevrolet El Camino. 350, TH400, 3.08 Posi 10 Bolt.



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