307 327 and 350 question

[skokie]

Is a 307 327 and a 350 the same block? If so then what makes a 307 a 307 same for a 327 and 350.

Thanks

[shortbed70]

No. The 307 is a differtent animal it has 3.875 bore and 3.250 stroke where the 327 and 350 share the same bore 4.000 the stroke is different 327 3.250 and 350 3.480. You can make a 327 out of a 350-307 combo by using the 307 crank rods and a 350 piston and have a 327-350-307 all in one. Oh yea the 307-327 blocks were never offered in 4 bolt mains. Hope this helps and if you have a 307 crank let me know.

[1972C10]

You can use good 350 rods dont have to use 307 rods Ive got two cranks one out of a 307 std std and one ready to put in just been turned .010 .010 It was supposed to be a large journal 327 crank but their the same cast so no telling.

[72C203503ONTHETREE]

Some Vette 327's came with 4 bolt mains, but its basically a 350 block, nothing special about them compred to a 350 block.

[8door]

Can we carry this a little further.
Is then the crank for the 327 and 350 different. I assume they have different rod journal locations. Or is it piston lenght diffrence?
If so do know the crank numbers for each?

[8door]

What I ment was is the piston ROD LENGHT different.Or maybe the wrist pin location.
Chris

[cochran63]

I have a 4-bolt 327 out of a vette in my 85. Wrist pin locations are different.

[8door]

cochran63
Doy you know of a book that illustates the engines ( I like pictures)
and cast part numbers for the different engines?

[Stroker]

This site has a lot of information for P/Ns
http://www.mortec.com/

[68c10owner]

to the best of my knowlege, the 327 was never offered as a 4 bolt main. i`ve heard alot of people say they came in vettes but all the info i`ve seen shows it did`nt. the only 4 bolt small blocks were 302, 350, and 400. if someone has a legit 4 bolt 327, i was to see the casting numbers. alot of people put the large journal 327 cranks in the 350 4 bolt block and i`m pretty sure the only 4 bolt small journal block was the 67` 302 and the 67` 350. my favorite small block is the 327 and i`ve done alot of research on them, in fact they are the onlt performance small blocks i`ve built for myself.

[GMC AMI]

Originally Posted by Stroker

This site has a lot of information for P/Ns
http://www.mortec.com/

Thank you very much for that link, One may never have too much info. I will stroke it for all it's worth. Mike

[1972C10]

the stroke is the difference in the crank rods and mains hook up in the same spot but a 327/307 moves the rod up 3.25 inch as opposed to the 350 3.48 the journals are the same diamter rod or main as in comparasion to a 350 large journal vs 327 large journal ..

Small journals are different smaller main journals.

[72C203503ONTHETREE]

I thought the 67 350 used the larger journals, but I may be wrong. Also after 67, the 327 stopped using the forged cranks and went to the nodular iron cast cranks along with the large journals. I had a 68-69 327 shortblock in my 83 El Camino(looked up the numbers). Had the original 327 in a 66 Malibu I had also, original four barrel dual exhaust car to.

[1BadSS]

My 327 is a 4bolt. Came out of a C60 pickup.

[68c10owner]

the 67 350 was the only small journal 350 since they went to the large journal starting in 68. they did`nt stop making the steel cranks after 67 cuz i had a large journal steel 327 crank that i was going to put in a 350 4 bolt block but the cast ones are easier to find.

like i said before, if you got a original 4 bolt 327, i want to see the numbers because all the info i`ve seen says they did`nt exsist.

[1BadSS]

Originally Posted by 68c10owner

the 67 350 was the only small journal 350 since they went to the large journal starting in 68. they did`nt stop making the steel cranks after 67 cuz i had a large journal steel 327 crank that i was going to put in a 350 4 bolt block but the cast ones are easier to find.

like i said before, if you got a original 4 bolt 327, i want to see the numbers because all the info i`ve seen says they did`nt exsist.

I'm not 100% certain on the reliability of what I was told. The po said it was a 4bolt because it was from a industrial truck, which I have my own doubts. I've never had the bottom end apart becuase it was a rebuilt shortblock.

[8door]

There is book titled "Chevrolet Pickup Parts Interchange Manual" lists interchangeable parts among 67 to 78 models includes engines as well as other items.
Has anyone seen or used this book?
Is it a good reliable source?
Worth buying?
Chris

[68c10owner]

i`m not trying to discredit anyone or call them a liar, i just want to see the numbers if someone has what they think is a legit 4 bolt 327. it`s really not a big deal but if they are real motors then i would like to see some info on them since the 327 has always been my favorite sbc.

[GMC AMI]

Originally Posted by 68c10owner

i`m not trying to discredit anyone or call them a liar, i just want to see the numbers if someone has what they think is a legit 4 bolt 327. it`s really not a big deal but if they are real motors then i would like to see some info on them since the 327 has always been my favorite sbc.

68c10 If you do not mind me asking, have you ever seen the suffix code end in yw? I saw you have done a lot of research on them. I know a lot of y codes are 327"s,I can not locate this one. The block casting # confirm it as a
block made in 67, which is correct for a 68 truck. #3892657 If you know thanks for the reply, Mike

[jimfulco]

All 350's came with the larger journals. The rest of the family joined in '68, although there were some early '68 cars built with leftover small-journal engines.

As far as 4-bolt 327's, I can think of 2 scenarios. One, they would not stop the assembly line because of a shortage of 2-bolt blocks. If there was a 4-bolt block handy, it would have been used. Two, there were a few high-performance 327's used in Chevelles & Novas in '68, rated at 325hp, but basically the same engine as the 350hp 327 from 66-67. These may have gotten some 4-bolt blocks. They also may have had forged cranks, but I don't know for sure.

[shortbed70]

8door I have the parts interchange manuel and there is ALOT of usefull steff. It has all part # heads blocks cranks balancers etc and also has most of the specs piston pin height rod lendths etc. Deffinatly worth purchasing. Heres what I came up with. My version 327 4 bolt 350 block 307 crank 327 piston stock deck height block leaves you with .025 clearance between top of piston and top of block deck. Same as stock 350. Now balance it and twist the BAJESUS out of it wooohoo. 4.56 posi traction make your own two lane blacktop. LOL

[68c10owner]

the 1967 SS 350 camaro was a small journal and was the only small journal 350. the L79 327, 350hp and the 325hp version, which were the same motors internally, had steel cranks but were 2 bolt mains. all small journal motors had steel cranks in them. the only small journal 4 bolt blocks were the Z28 302 in 67 and the 67 SS350 camaro.

Mike, you shoud be able to look the block casting up at mortec.com. to be totally honest with you, i never really got into the block codes since i never built one for a resto, just for racing, so i won`t be able to help you with your letter codes.

Cris, the reason i like these better is because of the short stroke allows them to rev alot faster and the small journal parts are slightly lighter. since the journals were smaller, they had less metal than the large journal. it probably doesn`t really make a difference but i was a dumb kid when i started building 327`s for racing and that was my logic for running the small journal stuff, even though the blocks were only 2 bolts and the rods could`nt handle the rpms for too long. i haven`t built one in about 10 years but the last one would rev to 8,000rpm and ran 12.18@114mph in a 65 chevelle and it was a pump gas daily driver. trucks are too heavy to run good times with them unless you have alot of compression ,deep gears, and a 4spd or high stall converter. i`m tempted to build another one for my 70 swb but in reality, they don`t make the torque to get trucks moving.

i want to make this clear that this is just a friendly discussion. i am in no way trying to discredit anyone or anything like that at all. i hope nobody has been offended.

[8door]

Anthony, I also have 68C10, but has a 350 1974 according to the number.
I was thinking of going back to a 327 when I'm ready to rebuild.
Why do you like them over others?
Chris (Looks like we stole this tread from skokie)