C2

[Michael Brophy]

Can someone tell me when a large journal crank was availible in a 327. I,m looking at a 63 with a # matching engine. The harmonic balancer is fat. My friend owns a machine shop and tells me to change the bottom end isn't something they would even attempt and probably wouldn't line bore. The block appears to have an 870 cast. Can I get some input?? Mike

[Duke W.]

Re: C2

The only large journal 327 is 1968. The reason the journal size was increased was to restore journal overlap in the longer stroke 350. The journal size was standarized in 1968 to allow use of the same bearings for all SBs.

The '63 and other year SHP/FI engines have the large 8" balancer. Medium performance engines got the smaller balancers.

The 327 doesn not need larger journals, but the early 327 rods are WEAK! Repeat, WEAK!

A better small journal rod went into production in '67, but for mechanical lifter 327s I recommend Crower Sportsman rods.

Duke

[Joe L.]

Re: C2

Michael------

...plus, the 1968 forged 327 crankshaft is one of the most difficult of all Corvette crankshafts to find and VERY expensive when you do.

In addition to that, I totally agree with your machinest; trying to convert an earlier 327 to the 1968 crank would be something I would NEVER recommend even attempting. You'd risk ruining the block and you'd gain nothing of significant value if it was all successful.

[William C.]

Re: C2

I certainly agree with the other posters, the small journal 327 block has been used in street and racing application for many years without problems, I certainly would not attempt to upgrade one now. A far better solution if you feel the need to upgrade would be to put the 870 block in storage and swap in an 010 or similar 350 block with four bolt mains that you can modify to your hearts desire.

[Andy #28359]

307 crank can be used for large journal 327

The 307 crank has the same stroke as a 327 and has large journals. Can be found in thousands of Chevys '68-'73. It's made from nodular iron not forged steel, good for normal street use.

[Mike Cobine]

Re: 307 crank can be used for large journal 327

The balance on the 307 crank is different than the 327 crank, due to different piston sizes. However, any decent machine shop can fix that and if you use a lightweight piston and pin, you may end up being right where you need to be.

Considering the millions of Chevy engines running a cast crank instead of forged, it is just fine for a street motor. Heck, my '85 3/4 ton Suburban had a cast crank in it, and it was HD on everything else. A couple engines in the race car ran cast cranks without problems, at least not bottom end related.