tune up specs 72 bbc - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jd4300fel · 03-09-2008, 07:37 PM

Hello,
I am looking for the original tune up specs for my 72, it has a 400 bbc aand a 400 tranny. I have recently added an HEI. I currenly have it set at 10 degres BDC, @ 650 RPM. I am also replacing the plugs which I am planning on gapping at .045.

Any details will be appreciated. I did check the FAQ but could not find what I am looking for

Regards,

Mike

kenm78 · 03-09-2008, 08:46 PM

I have Mitchell on demand online tech manuals and the settings are all for points timing is set at 8 degrees and idle is at 600 rpms and .035 gap and this is for 402 bbc. The manual specifys 400 bbc in the repair side but not on the tune up section. If it is running good and you have no pingging go with what you have!!

kenm78 · 03-09-2008, 08:54 PM

Ok did som more searching and found this

1976
400 BBC/454 BBC
Spark plugs light duty R45TS
Spark plugs heavy duty R44T

Gap for either is .045
Torque to 15 foot pounds

Timing is 8 Degrees BTDC.

RPM 600 auto trans.

jd4300fel · 03-10-2008, 01:23 AM

Thanks for the help, I will try bringing the timing down a little moer and see what happens for kicksI might hook up a vacum gauge an see what that shows

Longhorn Man · 03-10-2008, 03:50 AM

I'd stay with the higher timing if you aren't having any preignition problems.

03-09-2008, 07:37 PM	#1
jd4300fel Registered User Join Date: Aug 2002 Location: wheatland, Ca Posts: 427	tune up specs 72 bbc Hello, I am looking for the original tune up specs for my 72, it has a 400 bbc aand a 400 tranny. I have recently added an HEI. I currenly have it set at 10 degres BDC, @ 650 RPM. I am also replacing the plugs which I am planning on gapping at .045. Any details will be appreciated. I did check the FAQ but could not find what I am looking for Regards, Mike __________________ Mike K Friend of Bill W

03-09-2008, 08:46 PM	#2
kenm78 Broken Down Join Date: Dec 2006 Location: Choctaw, Oklahoma Posts: 1,267	Re: tune up specs 72 bbc I have Mitchell on demand online tech manuals and the settings are all for points timing is set at 8 degrees and idle is at 600 rpms and .035 gap and this is for 402 bbc. The manual specifys 400 bbc in the repair side but not on the tune up section. If it is running good and you have no pingging go with what you have!! __________________ kenm78 1982 Chevy 4X4 Project truck “It’s better to keep your mouth shut and let people wonder about your ignorance, than open your mouth and reveal all doubt”

03-09-2008, 08:54 PM	#3
kenm78 Broken Down Join Date: Dec 2006 Location: Choctaw, Oklahoma Posts: 1,267	Re: tune up specs 72 bbc Ok did som more searching and found this 1976 400 BBC/454 BBC Spark plugs light duty R45TS Spark plugs heavy duty R44T Gap for either is .045 Torque to 15 foot pounds Timing is 8 Degrees BTDC. RPM 600 auto trans. __________________ kenm78 1982 Chevy 4X4 Project truck “It’s better to keep your mouth shut and let people wonder about your ignorance, than open your mouth and reveal all doubt”

03-10-2008, 01:23 AM	#4
jd4300fel Registered User Join Date: Aug 2002 Location: wheatland, Ca Posts: 427	Re: tune up specs 72 bbc Thanks for the help, I will try bringing the timing down a little moer and see what happens for kicksI might hook up a vacum gauge an see what that shows __________________ Mike K Friend of Bill W

03-10-2008, 03:50 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: tune up specs 72 bbc I'd stay with the higher timing if you aren't having any preignition problems.



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