Engine pooped, couple of options, need some info

[jdfenske]

WELP! noticed some light pinging/sorta like *****ing sound when at high rpm. pulled heads off and what i see? 2 cracked pistons. and discoverd when i knocked them out seriously skuffed the walls....
block has already been bored, so, fu|< it, gonna scrap it.

couple of options, but, dunno how much i can mix old the new and new with old. i'd rather ask a couple of questions then tear down a bunch of engines and find out all this effort for nothing.

i have a NICELY rebuilt 350 it's the older late 70's, earily 80's, will the block work with the vortec heads? and will all the sensor bolt on stuff work; crank sensor, etc etc.

i also have a 94 350 with a spun crank main bearing, so, i might tear it all down and rebuild it, since it is a newer block, but, again, the question, will it work with vortec heads and all the sensor sh!t. on top of that i don't have time to move all my performance parts over to it, have to wait for another day

i'd rather go with the older block, as that car does run/drive, and holy, it's a strong running motor, i think that matched with the vortec heads and intake will be a sh1tter and gitter. on top of that i know how it performs, so, as of right now, unless someone points something out, it's going to be my selection. pull them out, swap heads/intake.

as far as i can tell and remember, all stroke and such is the same on the bottom end.

i guess my question is, will any 350 block work vortec stuff?

[436'd skylark]

vortec heads will bolt on to any conventional SBC, except the LT1 style motors. which means your intake and all that stuff will bolt on. however, the crank sensor might pose a problem, unless the sensor is built into the timing cover. the early blocks will obviously have no provisions for a crank sensor.

if the crank sensor jives, the only other problem I can think of would be the small combustion chambers in the vortecs. what are they 64 or 58cc?
Can't ever remember. anyway if the 70s motor is a 9.0:1 motor with the larger 78, 72 or 68cc heads, you will have crazy compression with the small chambers. possibly out of pump gas range.


As far as the engine with the spun main bearing, I would consider the block scrap. it will require an align bore, and hone to save it. that is a very pricey process that will run in the 300-400 dollar range easy, its generally not worth doing to any block unless its a numbers car, or its a very unique motor. almost always cheaper to buy a good core, especially true here since there are millions of SBCs.

[jdfenske]

thx for the fast reply. crank timing sensor is in the timing cover? or is it like a bolt on feature? having problem finding out this kinda info.

[436'd skylark]

Originally Posted by jdfenske

thx for the fast reply. crank timing sensor is in the timing cover? or is it like a bolt on feature? having problem finding out this kinda info.

I'm really not sure. I can't remember to save my life. typically thats where they are on GMs, but I can't say for sure.

[jdfenske]

some googling pulled this up

Chevrolet / Chevy*350 Engine (V8, 350 cid, 5.7L)

plastic timing cover? even so, says the crank sensor is in the timing cover.

no rush, i'll wait for some more replies.

[jdfenske]

no one here has ever put an older block against newer heads/intake?

[Sneakysportsman]

One thing I have not seen here is a mileage on the OLD block. This is critical in the event if the mains are weak and you are installing smaller combustion chambers, chances are you will be back at the motor stand again with a blown out bottom end of an older motor. I have a custom built TBI in a 95 4X4 with vortec heads. They flow so much better than any older heads that the compression ratio can and will change with every little mod you do to the motor. I know, I've been fooling with it for a year now, and today I put full length open headers on and took off down the road and about 25mph the tires started spinning and the trans blew. My suggestion for a blown 96-up vortec- FRESH BLOCK! Smoe of the older blocks are not drilled and tapped for a roller lifter spider. Vortec motors are roller blocks. If you are planning on using that .580 Lift cam, plan on shucking out a couple $100 to get the valve bosses trimmed. Max lift on a vortec head .500.

[jdfenske]

yeah i follow the lift problem. i'm not moving my performance parts over. that cam was for aftermarket alum heads i bought setup for higher lift. i plan on using the orginal OEM votec heads that came on the 96 itself. i don't have time if i start into it to move the parts over.. miles on the old block as the 70/80's one? dunno, speedo isn't hooked up. says 30,000 something. haha. but it's been rebuilt, i spoke with the guy that did it when i bought the car, new pistons, rods, wristpins, main and rod bearings, rings, cam bearings. i never did get the exact specs from him though. i went to try and get ahold of him and i was told he died few months ago. so, kinda going blind here without taking stuff apart, which i hate to do unnecessarily and upset anything.

but from my research, the crank sensors are in the timing cover, so as far as with sensors, i'm all set.

now the question is compression and CC displacement. i beleive the vortecs are 64? i may be wrong. can't remember. i suppose i'll have to take the heads off the older rebuilt block and do some measuring. But i'm also concerenced because i'd like to put the roller lifters that came with the 96 against the cam in the older bock, but mixing worn cam/lifters is a no no.

[436'd skylark]

Originally Posted by jdfenske

yeah i follow the lift problem. i'm not moving my performance parts over. that cam was for aftermarket alum heads i bought setup for higher lift. i plan on using the orginal OEM votec heads that came on the 96 itself. i don't have time if i start into it to move the parts over.. miles on the old block as the 70/80's one? dunno, speedo isn't hooked up. says 30,000 something. haha. but it's been rebuilt, i spoke with the guy that did it when i bought the car, new pistons, rods, wristpins, main and rod bearings, rings, cam bearings. i never did get the exact specs from him though. i went to try and get ahold of him and i was told he died few months ago. so, kinda going blind here without taking stuff apart, which i hate to do unnecessarily and upset anything.

but from my research, the crank sensors are in the timing cover, so as far as with sensors, i'm all set.

now the question is compression and CC displacement. i beleive the vortecs are 64? i may be wrong. can't remember. i suppose i'll have to take the heads off the older rebuilt block and do some measuring. But i'm also concerenced because i'd like to put the roller lifters that came with the 96 against the cam in the older bock, but mixing worn cam/lifters is a no no.

The older block will not accept factory style roller lifters. you will need to go aftermarket, which ain't very cheap.

[Sneakysportsman]

Look at the casting numbers in the valve guide valley. There are only two vortec castings. Check the last three digits in the casting #. 5.7 w/64cc is 906, I can't remember the one for the 5.0 but it is a 58cc. You can find the number ID on the internet maybe google or yahoo. Just search GM head casting numbers in your search. As for the block if you know it is fresh the it should be safe. Check the lifter alley in block you want to use, It may have on of the following.
1. 3 small pegs sticking up
2. No pegs
3. 3 pegs drilled and tapped for a roller spider.
If it has the pegs but they are not drilled, you can drill and tap them.
If it has no pegs you have to go after market.
If they are there drilled and tapped you are set.
I do have some of these parts including a vortec cam listed on ebay from my last project. If you have removed the Vortec heads from the original engine and it is a 5.7 then the casting is a 906 and you are good to go.