Thread: 427 truck block build questions

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I have a 470 trk blk, 4.00 eagle and had to clearance the bottoms of the cylinders for the rods.

Originally Posted by dmarrs

I have a 470 trk blk, 4.00 eagle and had to clearance the bottoms of the cylinders for the rods.

yep you have the older block .the one to look for is the later block that was 2 pc rear main seal and gm had the block cut out like the 454 on the bottom of the bores . 4.500 crank is just about a drop in. i pick up two of this type of block s new from EQ 7 years ago

I'm not sure the year of mine,but it does have a 2 piece rear

Originally Posted by dmarrs

I'm not sure the year of mine,but it does have a 2 piece rear

the last year before they went to from two to one pc seal was the years you want for a big crank i would say GM re tooled the block in the mild 80 s as this block had a casting on it for a knock ear .this block may have came out about the time GM did the first bow tie 10.200 bock as the bow tie was cut out like a 454 as well but the 427 tall deck did not have thick walls like the bow ties. i had a old 427 like yours no cut outs on the bottom of bores like 454 and was a super thick wall block would of took 4.400 bore EZ. some of the older blocks did say marine on them and i think were pre runners to the bow tie blocks