# 67 400 block



## mbspeed (Sep 25, 2012)

Hi all I have a 67 Pontiac 400 block I wanted build a stroker motor with this block the only difference from a H/O or R/A 400 is 4 bolt main correct or should I try find a better block /core its going into a 67 GTO 4 speed car want all forged parts in bottom end and will have edelbrock rpm heads the GTO has a 455 in it now but its got problems and needs come out of car and be rebuilt/repaired any info about 400 block will help I do know in the late 70's Pontiac used a block with less metal cast into it I know to stay away from them thanks......


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## Pinion head (Jan 3, 2015)

'67 400 blocks are typically one of the thicker 400 blocks. always smart, if it's a bare block that's been sitting unprotected, to run a ball hone up and down the bores a few times, wipe down cyl bores and examine for pitting. Mild pitting will disappear with an .030 overbore. it's when you are already at .030 and wanting to go .040, have to be careful. One can't see the rust damage from the back (water jacket) side. Usually, it's mild and inconsequential. One of my backup 4 bolt 455 blocks is at .030 currently, and in upcoming build, am going to have it vatted and sonic tested before partial hard block and boring.

early two bolt 400 blocks, will only have 2 motor mount bosses, so best to use them in '72 and earlier A body, or '69 and earlier F body applications. As far as 4 bolt caps, go, they really aren't needed in a build, like with naturally aspirated Edel round port 455-467. With stock head flow 87 cc Performer RPM (round port) heads, Edlelbrocks performer rpm package cam (RAIV clone), a Performer RPM intake and tuned Holley 850, only looking at 440 gross hp, on a Pontiac guru machine shop built 462...not exactly impressive, there are better alternatives, IMO. 

Tons of 400's and 455's have retained 2 bolt main caps in street/strip and strip builds up to the 600 gross hp level. at that higher level with 2 bolt caps, most use ARP main studs. Propperly fitting aftermarket 4 bolt billet caps, like the Program Engineering offerings, expect an extra $300-500 in expense in line boring and fitting the thrust bearing, depending on area of country/ who your engine builder is.


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## BearGFR (Aug 25, 2008)

:agree: That block will be a great foundation for a stroker build as long as it's in good shape. My 461 started out as a 'vanilla' YS coded '69, 2-bolt mains, and it's making somewhere in the neighborhood of 530-550 HP. The build is now close to 5 years old and has been driven a fair amount of miles (including the full 2013 Power Tour), seen a few passes on the strip, and still just percolating right along 

Bear


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## mbspeed (Sep 25, 2012)

yes mr.B the block is good 30 over 67 .......ALSO HAVE 69 YS BLOCK BUT THAT IS AT 60 OVER so not so good


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## BearGFR (Aug 25, 2008)

Awesome. Making a 461 out of a 400 takes a 4.25 stroke crank and a +0.035 bore (to use off the shelf pistons), so you're pert near there already.

Bear


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