Thread: chev 302's back from the dead

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well why not put a 327 crank into a 400 u get a 348 with big time revability

Originally Posted by gassersrule_196

well why not put a 327 crank into a 400 u get a 348 with big time revability

A lot of the "dirt-burners" out east are doing this on the extreme-"dry-slick" tracks.

thats where i heard it from, and old race motor guy <the guy who did my heads> some guys are a book of secrets i tell ya,

Originally Posted by gassersrule_196

thats where i heard it from, and old race motor guy <the guy who did my heads> some guys are a book of secrets i tell ya,

I am not a big fan of the 400 blocks but we use to run the 377's.
A lot of guy's that run the 377's/348's don't have the new chassis to hook the car up off the corners so they cut the stroke back and try to move the power-band up-stairs.

Originally Posted by jerry clayton

Don't they know that there's a bearing set to put the 350 sized crank into the small journal block?

Thats not possible to put a large journal 350 or 327 crank into a small journal 265-327 block unless you have the block mains machined (line bored) to fit the large journal crank. unless you ment you can buy (from where?) a bearing spacer set for putting a small journal 283 crank into a large journal 327 or 350 block making a 302? otherwise the only bearing spacers we've seen is for putting a 350 or large journal 327 crank into a 400 block since a 400 has larger main journals than a 350 or large journal 327. But the small journal engines were the 265-283-302-327 1967 and older when the 350 came out in 1968 chevrolet switched to the large main journals 307 and up. 1965 an older 265-283-327-348-409 had stock forged steel cranks and its rare to see a stock motor with a forged crank after 1965 when they switched to using stock cast iron cranks.
But otherwise its what i talked about at the machine shop with the guys and i thought i'd share it with you all.

you can ahve the cranks turned down

Any one ever build an engine using a 1975 262 SB Chevy 3.100 crankshaft . I had one of these 262s in a 1975 Monza with a 4 speed . I ran a Comp cams 268H 218/050-454 lift with a 600 Holley D/P on a non-EGR cast iron intake . That car ran strong . I think it had #601 head stock . The standard bore is-3.671 better then the 267s -3.500

Originally Posted by tango

I think I would rather try my luck with boring a 283 block to 4" . And running the stronger S/J 327 rods that still only have 11/32 rod bolts . The 327 I am making is a L/J 1971 350 block with 1972 307 crank it has the stronger rods with 3/8 sps bolts . COOL

Yeah you could bore your 283 .125 thousands over to make a 4" bore. you could also bore your 307 to a 4" bore .125thousands over since its a large journal 283 block with a large journal 327 cast iron crank. all those rods are the same in those stock motors there all a 5.7 cast iron rod with 3/8 bolts and rated for only so many RPMs before they fly apart. the only thing chevrolet really changed was the piston pin height for the different length crank strokes but otherwise all used a 5.7 rod.

Originally Posted by speedy55779

Yeah you could bore your 283 .125 thousands over to make a 4" bore. you could also bore your 307 to a 4" bore .125thousands over since its a large journal 283 block with a large journal 327 cast iron crank. all those rods are the same in those stock motors there all a 5.7 cast iron rod with 3/8 bolts and rated for only so many RPMs before they fly apart. the only thing chevrolet really changed was the piston pin height for the different length crank strokes but otherwise all used a 5.7 rod.

OH,NO!!!!HERE WE GO AGAIN!!!

Originally Posted by gassersrule_196

you can ahve the cranks turned down

true i over looked that but why would you want to? it would be like putting a 350 crank in a 283 block for example.

Originally Posted by erik erikson

OH,NO!!!!HERE WE GO AGAIN!!!

Hey tango started it

The 307 blocks are not so thick like the 283 blocks are in the bore . I would build the 307 as a 307 or go 30 over to a 311 . All SB Chevy connecting rods are forged steel . And have sample tested to 9500 lbs tension and 1450lbs in compression . With ARP bolts installed these rod should be good to 7500 RPMs

Originally Posted by tango

The 307 blocks are not so thick like the 283 blocks are in the bore . I would build the 307 as a 307 or go 30 over to a 311 . All SB Chevy connecting rods are forged steel . And have sample tested to 9500 lbs tension and 1450lbs in compression . With ARP bolts installed these rod should be good to 7500 RPMs

they are the exact same block but the 307 has large main journals thats the only diff.

Next time you have the heads off a 283 and a 307 take a good look at both blocks . Also measure the wall thickness of both . The blocks made after 1967 can not go over 60 on the bore safely .

the 307 came out around the same time as the 350. chevrolet had to get rid of all its 283 stock so they stroked them out to a 307 by putting 327 large journal cranks in them to introduce another new engine to the market instead of keeping the 283's around