Chevy72402 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

conman · 06-09-2002, 09:04 PM

I read in your signature that you just rebuilt your 402. What kind of build up did you do. I also have a 72 402 bb in my longhorn. I'm thinking about rebuilding in the future.

chevy72402 · 06-09-2002, 09:30 PM

I have keith black hyperutectic pistons with a .800 raise, a comp cam extreme energy 262H cam, a weiand action plus intake manifold, proform hei distributor, I had it balanced, polished, the only thing that I didn't have done was have it deckplated. I am thinking about going to a holley street avenger carb 670 cfm is what tech support said to use. I like my edlebrock but want a few more ponies and more throttle response so I am going back to the Holley. I had it bored over 40 also

chevy72402 · 06-09-2002, 09:35 PM

oh yeah I also redid the valve guides and put new spings and I think they were manley valevs in. I had the seats ground. Needless to say I wanted to do this one time and do it right!

conman · 06-10-2002, 07:20 AM

You have any idea how much at the rear wheels? What kind of difference do you notice?

chevy72402 · 06-10-2002, 02:47 PM

no idea as of now. I have been breaking the engine in slowly and don't want to blow it appart. I do notice a difference though. Having everything balanced and blueprinted really makes it a lot smoother and more torque. Can't wait to get my new carb. I will probably order it today! wohoo another $400.00

Orence1 · 06-10-2002, 04:09 PM

I have a 402 built very much the same way. I might have a bit more work done on the heads but I have the KB pistons and a similar cam set up. My builder who is a race guy tells me that I need at least a 750 cfm carb. I had a Holley 750 custom built for it. Are you sure the 650 cfm carb won't restrict that all important airflow you need to unleash all that power? Just another viewpoint for you to consider.
Larry

chevy72402 · 06-16-2002, 02:28 AM

That is what the guy at Holley told me anyway... I am not sure. I haven't bought it yet so I guess it's on hold till I find out more info. What else did you have done to your heads?? I wanted to keep a stock appearance (even though I had to buy a new intake cause mine was cracked) but yet build it to last through me and generations to come.

LILREDGMC · 06-16-2002, 10:22 AM

Which casting number heads are you using. Open or closed chamber? Have an estimate on CR? Mine is still at the shop, waited for 030 bore.

chevy72402 · 06-16-2002, 02:11 PM

I left my receipts in Michigan at My fiance's house.... I will have to get them.... dang it! as for casting numbers I don't remember what they were. I know that they were the factory ones but not sure what style.....

batboy · 06-16-2002, 11:25 PM

Most hotrodders will use a 750 CFM carb on a big block. But, if you want good low end torque and have a fairly mild cam (like the 262H), there is nothing wrong with using a smaller 650 to 670 carb. You don't want to use high revs with those big blocks anyway and the big carbs are more for full throttle, high RPM stuff. For trucks, I like the small valve oval port heads (open chamber if you can find them), a good cam for low and mid range, headers, and a modest carb. Talk about a stump pulling torque monster.

06-09-2002, 09:04 PM	#1
conman Registered User Join Date: Jan 2002 Location: Fayette, Alabama Posts: 155	Chevy72402 I read in your signature that you just rebuilt your 402. What kind of build up did you do. I also have a 72 402 bb in my longhorn. I'm thinking about rebuilding in the future. __________________ Fayette Alabama

06-09-2002, 09:30 PM	#2
chevy72402 FARMER/RANCHER Join Date: Apr 2001 Location: SD Posts: 597	I have keith black hyperutectic pistons with a .800 raise, a comp cam extreme energy 262H cam, a weiand action plus intake manifold, proform hei distributor, I had it balanced, polished, the only thing that I didn't have done was have it deckplated. I am thinking about going to a holley street avenger carb 670 cfm is what tech support said to use. I like my edlebrock but want a few more ponies and more throttle response so I am going back to the Holley. I had it bored over 40 also __________________ 1972 chevy super, long box, 402 big block (2,000 miles on rebuild) 2wd tach, tilt, tool box on bedside, a/c, sliding rear window, orange and white. 1972 Chevy Blazer 2wd, tach, tilt, a/c, my first engine overhauling experience, Orange, with white top 2006 Gmc Sierra, XM, Z-71, dark blue, onstar, leather, rear entertainment (audio only) heated seats, (the wife loves that feature) upgraded tires immediately after purchase to Goodyear Wrangler AT/S (hate those rock throwers that come from the factory) BWC

06-09-2002, 09:35 PM	#3
chevy72402 FARMER/RANCHER Join Date: Apr 2001 Location: SD Posts: 597	oh yeah I also redid the valve guides and put new spings and I think they were manley valevs in. I had the seats ground. Needless to say I wanted to do this one time and do it right! __________________ 1972 chevy super, long box, 402 big block (2,000 miles on rebuild) 2wd tach, tilt, tool box on bedside, a/c, sliding rear window, orange and white. 1972 Chevy Blazer 2wd, tach, tilt, a/c, my first engine overhauling experience, Orange, with white top 2006 Gmc Sierra, XM, Z-71, dark blue, onstar, leather, rear entertainment (audio only) heated seats, (the wife loves that feature) upgraded tires immediately after purchase to Goodyear Wrangler AT/S (hate those rock throwers that come from the factory) BWC

06-10-2002, 07:20 AM	#4
conman Registered User Join Date: Jan 2002 Location: Fayette, Alabama Posts: 155	Ponies and torque You have any idea how much at the rear wheels? What kind of difference do you notice? __________________ Fayette Alabama

06-10-2002, 02:47 PM	#5
chevy72402 FARMER/RANCHER Join Date: Apr 2001 Location: SD Posts: 597	no idea as of now. I have been breaking the engine in slowly and don't want to blow it appart. I do notice a difference though. Having everything balanced and blueprinted really makes it a lot smoother and more torque. Can't wait to get my new carb. I will probably order it today! wohoo another $400.00 __________________ 1972 chevy super, long box, 402 big block (2,000 miles on rebuild) 2wd tach, tilt, tool box on bedside, a/c, sliding rear window, orange and white. 1972 Chevy Blazer 2wd, tach, tilt, a/c, my first engine overhauling experience, Orange, with white top 2006 Gmc Sierra, XM, Z-71, dark blue, onstar, leather, rear entertainment (audio only) heated seats, (the wife loves that feature) upgraded tires immediately after purchase to Goodyear Wrangler AT/S (hate those rock throwers that come from the factory) BWC

06-10-2002, 04:09 PM	#6
Orence1 Registered User Join Date: Jan 2000 Location: Bothell, WA Posts: 548	I have a 402 built very much the same way. I might have a bit more work done on the heads but I have the KB pistons and a similar cam set up. My builder who is a race guy tells me that I need at least a 750 cfm carb. I had a Holley 750 custom built for it. Are you sure the 650 cfm carb won't restrict that all important airflow you need to unleash all that power? Just another viewpoint for you to consider. Larry

06-16-2002, 02:28 AM	#7
chevy72402 FARMER/RANCHER Join Date: Apr 2001 Location: SD Posts: 597	That is what the guy at Holley told me anyway... I am not sure. I haven't bought it yet so I guess it's on hold till I find out more info. What else did you have done to your heads?? I wanted to keep a stock appearance (even though I had to buy a new intake cause mine was cracked) but yet build it to last through me and generations to come. __________________ 1972 chevy super, long box, 402 big block (2,000 miles on rebuild) 2wd tach, tilt, tool box on bedside, a/c, sliding rear window, orange and white. 1972 Chevy Blazer 2wd, tach, tilt, a/c, my first engine overhauling experience, Orange, with white top 2006 Gmc Sierra, XM, Z-71, dark blue, onstar, leather, rear entertainment (audio only) heated seats, (the wife loves that feature) upgraded tires immediately after purchase to Goodyear Wrangler AT/S (hate those rock throwers that come from the factory) BWC

06-16-2002, 10:22 AM	#8
LILREDGMC Registered User Join Date: Oct 2001 Location: Pittsburgh, Pennsylvania USA Posts: 461	Heads Which casting number heads are you using. Open or closed chamber? Have an estimate on CR? Mine is still at the shop, waited for 030 bore.

06-16-2002, 02:11 PM	#9
chevy72402 FARMER/RANCHER Join Date: Apr 2001 Location: SD Posts: 597	I left my receipts in Michigan at My fiance's house.... I will have to get them.... dang it! as for casting numbers I don't remember what they were. I know that they were the factory ones but not sure what style..... __________________ 1972 chevy super, long box, 402 big block (2,000 miles on rebuild) 2wd tach, tilt, tool box on bedside, a/c, sliding rear window, orange and white. 1972 Chevy Blazer 2wd, tach, tilt, a/c, my first engine overhauling experience, Orange, with white top 2006 Gmc Sierra, XM, Z-71, dark blue, onstar, leather, rear entertainment (audio only) heated seats, (the wife loves that feature) upgraded tires immediately after purchase to Goodyear Wrangler AT/S (hate those rock throwers that come from the factory) BWC

06-16-2002, 11:25 PM	#10
batboy Registered User Join Date: Mar 2000 Location: Kansas, USA Posts: 175	Most hotrodders will use a 750 CFM carb on a big block. But, if you want good low end torque and have a fairly mild cam (like the 262H), there is nothing wrong with using a smaller 650 to 670 carb. You don't want to use high revs with those big blocks anyway and the big carbs are more for full throttle, high RPM stuff. For trucks, I like the small valve oval port heads (open chamber if you can find them), a good cam for low and mid range, headers, and a modest carb. Talk about a stump pulling torque monster. __________________ 1972 Chevy 3/4 ton Camper Special 1970 Chevy big block parts truck 1989 Chevy Blazer Silverado 4X4

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