402 p/u block and miniscule 3.935 bore - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ed 72 Sierra Grande · 10-30-2012, 08:43 PM

Wanting to give the old 402 some love I purchased the "Killer BB Chevy Book(SA/Tom Dufur) and before getting to the 3rd chapter MR. Tom stops me with this:

"Four Gen IV bore sizes if you count the 366T tall deck truck blocks with their miniscule 3.935 inch bores, but I'm not counting them because they are totally unsuitable for any performance big block buildup"

Thanks Tom.

Hoping my truck brothers back me up and tell how far I can take the 402.
I would like streetable performance and great towing for the 8 lugger.

What can I do?? What should I do?? Help very much appreciated. Thanks

EdF

clinebarger · 10-30-2012, 10:33 PM

402's have a standard bore size of 4.125"

Ed 72 Sierra Grande · 10-30-2012, 11:19 PM

Quote:

Originally Posted by clinebarger

402's have a standard bore size of 4.125"

Cline,

My bad. Just re-read and realized the author was quoting the 366
which till now had never heard of.I learn something new every day.
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**425HP409** · 10-30-2012, 11:52 PM

Chevy built two truck engines on the Mark IV Block. They made a 366 and a 427. These were called "Tall Blocks" because the block deck height was .400" taller than a passenger big block. They were built very heavy duty and had 4 ring pistons that were very heavy, not great for performance, but great for torque. They also took an intake built for them due to the taller deck height. Because of their taller deck height, racers in the sixties used them to make large displacement stroker motors.
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10-30-2012, 08:43 PM	#1
Ed 72 Sierra Grande Registered User Join Date: Jul 2010 Location: Whittier Ca Posts: 172	402 p/u block and miniscule 3.935 bore Wanting to give the old 402 some love I purchased the "Killer BB Chevy Book(SA/Tom Dufur) and before getting to the 3rd chapter MR. Tom stops me with this: "Four Gen IV bore sizes if you count the 366T tall deck truck blocks with their miniscule 3.935 inch bores, but I'm not counting them because they are totally unsuitable for any performance big block buildup" Thanks Tom. Hoping my truck brothers back me up and tell how far I can take the 402. I would like streetable performance and great towing for the 8 lugger. What can I do?? What should I do?? Help very much appreciated. Thanks EdF __________________ Ed F 1972 Sierra Grande White Top Medium Olive 402 bb / Camper Stock, Loaded, Straight & Aged Nicely, No Tilt Original Resto would be nice $

10-30-2012, 10:33 PM	#2
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: 402 p/u block and miniscule 3.935 bore 402's have a standard bore size of 4.125"

10-30-2012, 11:52 PM	#4
425HP409 425hp409 Join Date: Oct 2008 Location: Prosper Texas Posts: 837	Re: 402 p/u block and miniscule 3.935 bore Chevy built two truck engines on the Mark IV Block. They made a 366 and a 427. These were called "Tall Blocks" because the block deck height was .400" taller than a passenger big block. They were built very heavy duty and had 4 ring pistons that were very heavy, not great for performance, but great for torque. They also took an intake built for them due to the taller deck height. Because of their taller deck height, racers in the sixties used them to make large displacement stroker motors. Posted via Mobile Device __________________ Charles 68 SWB, Dad bought new, now 396 & factory ac 64 Impala SS, 409 425HP, 4 speed AC 64 Bel Air Wagon, 400 Small Block 57 Bel Air all original 283 w/Factory Air 77 GMC Sprint, 454/425HP 67 Olds 442, all original 90 ZR1 Corvette



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