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Getting my ducks in a row. Want to build sbc stroker and still retain aluminum finned valve covers, winters intake, front oil fill tube with threads to accommodate pvc valve and road draft tube at rear of motor next to distributor. ( 67 L-79 look alike). Question is what blocks are large journal and still have breather hole at rear of block? I read it somewhere here but couldn’t find it again. Where these all 2 piece rear main seals? Thanks
2025 C2 of the Year ('64-'66) Finalist - Unmodified
Not sure about the blocks, but I just had a 350 crank turned down to the small journal size and it worked out fine. Some people have made 383's this way as well. You can also have your small journal block line bored to the large journal size.
I am only aware of the 1967 small blocks (283, 302, 307, 327, & 350) which were the last year for the draft tube, I think. Others may know of a later block. The 67 was the first year for the large journal crank and block. Might be rather hard to find with everyone going LS.
You are looking for a really hard to find block. All othe 67 blocks other than what DZ mentions are small journal. I would run a PCV valve in the intake behind the carb and use the filler tube as a clean air source and run a regular 350 block.
A service only block, part number ending in 512 could also be processed by GM for both bearing sizes or align bored in the field to increase bearing size from small to large. These blocks like the '67 ...657 blocks were processed with bearing retention notches for both small and larger bearings, so all that's required for field increases to large bearings is align boring to the larger size.
I used AFR aluminum heads and the OEM valve covers fit fine with thin head gaskets. I did use the shortest rocker arm lock nuts that i could find though.
Plenty of room with the raised rails on the heads.
By the way, just to repeat, and as described by Duke, ANY 62-67 327 block can be used to build a 350 or 383. Yes, a little machining is required as well as extra money, but an end result can be a more or less bone stock appearing 283.
I have a fuel injected SB400 in the 56 which I have attempted to duplicate the appearance of a 57 FI 283 with 9fin valve covers.
By the way, just to repeat, and as described by Duke, ANY 62-67 327 block can be used to build a 350 or 383. Yes, a little machining is required as well as extra money, but an end result can be a more or less bone stock appearing 283.
I have a fuel injected SB400 in the 56 which I have attempted to duplicate the appearance of a 57 FI 283 with 9fin valve covers.
d
I don't recommend increasing main bearing sizes on ...870 blocks or turnng down longer stroke cranks to small main size. The nice thing about the ... 657 and ...512 blocks is that they were designed to be processed for both bearing sizes, and in addition to having notches for both bearing sizes I believe they have thicker main bearing webs and more clearance for 350 cranks, but still might need a little grinding along with "stroker rods" to take a 3.75" crank.
And, most importantly they have the rear crankcase vent hole, so you can configure an early style PCV system. And if it's a '67 with the original block even the best NCRS judge would could never tell that it's a stroker cheater motor.
By the way, just to repeat, and as described by Duke, ANY 62-67 327 block can be used to build a 350 or 383. Yes, a little machining is required as well as extra money, but an end result can be a more or less bone stock appearing 283.
I have a fuel injected SB400 in the 56 which I have attempted to duplicate the appearance of a 57 FI 283 with 9fin valve covers.
Larry,
I first prototyped this on a junk 350 block just to see if it would work. It did.
I used brass fittings with 3/8in pipe thread (I probably could have used 1/4in pipe thread fittings).
I drilled a hold through the bell housing flange, then a hole through the rear of the block next to the distributor hole.
Using various brass fittings and brass pipe, I fabricated plumbing going into the rear of the lifter valley and plumbed pipe all the way to the very front of the lifter valley. I put a cap on the front end of the pipe with 3 small holes drilled into the cap. Since I felt that liquid would flow toward the rear of the valley, mainly only vapors would be up front of the valley.
Coming up from the rear of the block, I used fittings and 5/8in copper tubing, hose and fittings into the vacuum port at the left rear of the plenum with the same (replacement) PCV valve that is used on the right rear of 63 FI units.
The oil fill tube up front has a regular AC/OIL chrome push on breather cap.
Been like that for over 10yrs and seems to be a good PCV system.
Here is a good view from the left side, with the ignition shielding in place.
I didn't even go thru the bellhousing flange, I put a 3/8" NPT thread in the rear block wall just below the intake in a place it didn't interfere with anything.. A brass street ell, and then a hose barb and then fuel line to the base of my throttle body.
As I use an oil splash shield in the lifter valley I didn't bother to put any type oil separator in.
I have no excess oil consumption and no oil smoke.
BTW, those are NOT the rocker arms I used for the build, I don't remember why i had them loosly installed, but there was some reason, checking valve cover clearance, or something for roller rockers.
I didn't even go thru the bellhousing flange, I put a 3/8" NPT thread in the rear block wall just below the intake in a place it didn't interfere with anything.. A brass street ell, and then a hose barb and then fuel line to the base of my throttle body.
As I use an oil splash shield in the lifter valley I didn't bother to put any type oil separator in.
I have no excess oil consumption and no oil smoke.
BTW, those are NOT the rocker arms I used for the build, I don't remember why i had them loosly installed, but there was some reason, checking valve cover clearance, or something for roller rockers.
Doug
Doug,
This was just an experiment for me, and since I had never done anything like it before, I was kinda fabricating as I went. So far, it has worked fine, and if I ever did it again, I have learned some lessons!
My ultimate goal was to have a functional PCV setup WITHOUT any holes in the valve covers.
And since I was able to get extra bosses welded, drilled and tapped for staggered bolt pattern covers, that was another plus! So I more or less have 400+cubes that somewhat resembles a 57 FI 283.
Stroker engine build
