350 4 bolt main block

[luxeryvic]

i found a 350 4 bolt main block and crank for $150 is this a good deal, i dont know wat it is out of but i plan on boring and stroking it anyway

thanks for the help

[wafrederick]

There should be numbers on the block,the right front and left rear.Most 350 blocks should have 5.7 on the rear on most.Any machine shop will probally find out for you.What side is the dipstick tube on?Check if the crank is a cast or steel crank,use a small hammer for this test and tap on on it with the small hammer.If it is a cast crankshaft,a dead thud should ring out and a steel,a loud ringing noise.

[MrPbody]

Actually, pre-77 blocks will rarely have "5.7" cast onto them. The "litre" thing didn't start here (USA) until the late '70s. Virtally ALL early blocks are "driver's side dipstick". It is accepted that those blocks MAY contain a higher percentage of nickel. No factual info there...

The "dull thud" you hear means the crank is cracked, not "cast". The "ring test" is not to be considered reliable, and for it to be even remotely accurate, the timing gear AND Woodruff key must be removed. Magneflux is the ONLY practical method that IS reliable. To identify a cast crank from a forging, look at the "parting line" that runs the length. A "narrow" one (about 1/16" wide) indicates cast, while a wider one (anywhere from 1/4 to 1/2") is a forging. This is only true with factory cranks. Aftermarkets have many things that can disguise the true origin. A Rockwell test may be necessary for those.

The MOST sure way to tell is to look up the casting or forging number. The vast majority of 2-piece rear seal castings have a number ending in "442". The majority of 2-piece rear seal forgings are 1182. There ARE others, but 95% (or more) are these two numbers.

Measure the bore. If the block is already .040" or more "oversize", it may be worthless. If it's .040" but shows no wear, it MAY "clean" at .060. While there are larger oversize pistons available, .060" is considered the practical limit.

Jim

[luxeryvic]

its a 2 piece rear seal and it hasnt been bored , but if it measures good it it worth $150 ive seen bare 350 blocks at flea markets for like $300 , $150 seems good to me

[luxeryvic]

and cant u use water jacket filler like hard-blok, isnt that wat it is for ( boring oversize ) ?

[luxeryvic]

and it doesnt matter wat the crank is i plan on putting in a stroker crank, so is $150 worth it?

[silicon212]

Originally Posted by wafrederick

There should be numbers on the block,the right front and left rear.Most 350 blocks should have 5.7 on the rear on most.Any machine shop will probally find out for you.What side is the dipstick tube on?Check if the crank is a cast or steel crank,use a small hammer for this test and tap on on it with the small hammer.If it is a cast crankshaft,a dead thud should ring out and a steel,a loud ringing noise.

You will only see 5.7 on 'newer' blocks with one-piece rear seals.

Dipstick tube is on left for <='79 blocks, right side for >='80 blocks.

You don't even need to hit the crank with a hammer to determine whether it is cast or forged. A forged crank will have a wide 'parting line' across the throws, where a cast crank will have a very thin parting line.

[silicon212]

Originally Posted by luxeryvic

and cant u use water jacket filler like hard-blok, isnt that wat it is for ( boring oversize ) ?

No, that's for strengthening the bores for drag racing - it displaces water and is not to be used in a street engine, for any length of time at all.

When you get into overboring a cylinder block, the cylinder walls become very thin and may even become porous. If that is the case, the block is toast. Even though Mr Peabody says that .060 is the practical limit (and it is), I wouldn't want to run more than a .030-.040 overbore in a street engine that needs to be reliable. .060 overbores have a knack for running hot and remember again that the larger you overbore, the more likely you are to hit a porous spot.

[MrPbody]

Silicon212,

While what you're saying isn't entirely incorrect, there are a few points to make.

First, .060 over with a small block is quite common without trouble. I wouldn't use one of the modern "thin wall" blocks that way without sonic-testing first, but even those seem to be okay for the most part. The "running hot" thing is more myth than fact. If the cooling system is in good order and the tune is right, it'll be fine.

Another one. Filling the block. While it IS used mainly for race engines, to rigidify (is that a "real" word?) the cylinder walls, it isn't uncommon for certain blocks to be done for street use. 400 small blocks greatly benefit from it, as their walls are woeful. THAT'S a small block I wouldn't like at .060 over, though I have seen them work fine. The majority of the heat from combustion "lives" in the top 1" of the bore, if all things are correct (mixture, timing). If the block is "filled" to within 1 1/2" from the top (water pump openning), the cooling system will take away the heat okay. The real issue here is the oil. Since the bottom portion of the water jacket is solid, the oil in the crankcase can't dissapate heat there, and it needs to. The solution is to install an external oil cooler. We have several customers with small blocks ruinning this way for years in street cars, without heating problems.

FWIW

Jim

[luxeryvic]

so back to my question , lol is $150 a good price?

[silicon212]

If the block is in good rebuildable condition, it sure is.

[wafrederick]

A very good price and they are very hard to find.You are very lucky to find the block.

[Blue Bowtie]

I recently picked up a running 350 4-bolt block for $75. They are available. This was from a 1979 1T truck, with a ton of miles, and only 1.8 thou taper in the worst bore. Cast crank and bearings looked very good. I'm thinking a forged rotating assembly with a bit more stroke will work out nicely.

[luxeryvic]

ok i thought it sounded good, i think i will get it, i want to make it a stroker and i have a set of 305 heads to boost compression, along with high compression pistons i want the compression high itll be a race engine so it doesnt matter what gas it runs on, anyway any cam or intake suggestions, itll be goin in an early 80's compact car and the carb will be a modified q-jet, i bought a book like everyone suggested and it has step by step procedures.
thanks for the input

[MrPbody]

One of the advantages of a high compression "race" engine is to rev it hard. If you stick with the 305 heads, you won't have that luxury. We've learned in recent years, "flow trumps compression".

What that means, is a head that flows better but has a full point lower compression on a given engine, will usually out-perform the higher compression engine. Though it's not a Chevy, I have an example of "real world" power. One of my customers runs a '74 T/A in F.A.S.T. Class (Factory Appearance, Stock Tire). When he first built it, he used 1970 #64 heads. These heads provided 11.5:1 (milled) on his 462 CID engine. They were ported by a well known Pontiac shop (265 CFM intake flow at .550" lift). Then came a "rule change" that required him to install the correct casting number for the year. That would be the "4X", with 108 CC chambers, yielding a static compression ratio of about 8.4:1. We milled .050" off them, bringing it all the way up to 9.6:1. We ported them extensively (285 intake flow at .550" lift). It had dynoed 350 RWHP before. No other changes, it now dynoed at 388 RWHP. The car picked up 3 MPH as well, indicating the increase in power. So, even with significant loss of compression, it still picked up power.

I would recommend a pair of Vortecs if your budget can't stand some good aftermarket heads. A little exhaust port work and Vortec is an EXCELLENT performer. And, at 64 CCs, you'll still get a good static compression "number".

As for the cam, either a solid'/flat tappet or solid roller is the only thing to bother with in a race engine. We use Comp pretty much exclusively, but there are others. With 11:1, something in the 260-270 range @ .050" lift (intake duration) would be right. Always add 6-8 degrees for the exhaust. The .620" lift rollers are VERY popular these days, expecially in bracket cars. Flat tappets should stay at or under .600" lift due to spring requirements and lifter "load".

Cut zero corners regarding the valve train. Buy parts based on quality, too, not price. A stable valve train in a small block is one of the keys to a long, powerful "life".

If you're going to use the Q-Jet (good carb, BTW), Edelbrock Performer RPM "Air Gap" would be a good choice, but it needs some porting and finish work for a race application. Cliff's High Performance in Mt. Vernon, Ohio, is THE place for Q-Jets for racing. He has customers that run 9s in NHRA SS cars with Q-Jet.

Victor or Super Victor would make more power up high, but are better suited to Holley carbs. Victor Jr. is only suited to smaller cubed engines or 2-bbl. (circle track) applications. If it doesn't say "Edelbrock" on it, it's designed to LOOK like an Edelbrock. Edelbrock wears engines out testing.

FWIW

Jim