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Discussion Starter · #1 ·
Sup guys. THis is going to be a lengthy post because I new to hot-rodding and i'm pretty much uneducated when it comes to the internal combustion engine. Some of you know I got lucky and scored free .327 bored .040, S/R Torquer heads and Scorpion 1.5 Roller Rockers with Hooker long tube headers mated to a 700R4 tranny. It's been fun tearing it apart finding out how they go together and they function mechanically. It makes me miss the days of working on F-15 and F-16 turbine engines in the USAF. The ONLY frustrating part is decoding engine numbers and not having the cashflow to finish it NOW!!!!!! Anyway while going thru the motor I found the camshaft was trashed. Flat spots everywhere. I've decided to go to a roller cam setup and purchased a kit from Fastcoauto.com for about $750.00. It comes with a Engine Works Cam with .480 lift (whatever that means), an adapter (washer) for the cam, double roller gears with chain, Comp Cams pushrods, and Morel Morel roller lifters. Oh yeah and something called a Thrust Button!!!!!!! I guess my first question would be is this a good buy????? Or did I get raked over the coals?????

Next Question is the main and rod bearings. during diassembly I discovered that the flash chrome plating (if that's what it was) was worn off and a copper colored base metal was exposed. the p/n's i got from the are Clevite 77's MB 2508 P and CB 663 P. Everything I've read suggests to me that these are standard size bearing/journals. Is this true??? those p/n's are tricky to find. Any help would be awesome.

Engine Stampings; So I know I have a .327 because of the stamping on the drivers side rear of the block has p/n 3914678 and the crank has a stamping of 3941174 with a Bore vin# of 4.00. What I don't know is if I have the "large" or "small" journal cranks I read about. Once again, any clarification is appreciated.

Connecting Rods; I have simply given up on trying to identify them. I know they are GM rods so I'm left to ASSume they're stock to that crank.

The final thing that I wanna know is given ALL the information I've spewed out, what kind of HP/TQ am I realistically looking at???? I know this is a mouthful, but, you guys are all I've got at this point. Thanks in advance for answering all my newbie questions.
:dontknow::confused2::help::newbie:
 

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Tony,, can you look on the back of motor near the forging # and get the date code?? sholud look like A157.. A=January, 15 is the day and 7 would be 1967,, just an example,, I will goggle the forging # on the crank,, I ground cranks for 6 years,, loved the steel GM cranks,, and if there was no 0.10 or .020 on the bearings sounds like a STD crank,, Matty man
 

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3941174 is the large journal cast crank going by 1 web site,, is the parting line on the crank(stand it straight up) and look at the casting line, its either thin or thick,, if it is a very small thin it is cast and if it is thick your in luck, a rare steel crank,, old truck engine,, good for power, RPM`s,, what size socket did you use to take the rod caps off with?? either a 1/2 or 9/16,, that will also determine a small or large journal,, Matty man
 

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You should probably replace your valve springs and check them for coil bind at max lift. Any good machine shop can check spring height for you. Start shopping around for a good machine shop. Not the cheapest machine shop, but one with a good reputation and willing to answer your inevitable questions. Good machine work is critical to motor longevity and maximum power. You're going to need block work, crank work, cam bearings, rod resizing, head work and more. There are no shortcuts with machine work...Good Luck
 

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From what you mentioned about the bearing inserts being copper colored, you are going to need the crankshaft checked. Usually when copper is showing, the babbit surface is worn off, and crank will have enough wear to need a re-grind.

Going with a roller cam set-up is a good idea, with today's oils not having the anti-wear characteristics of the old days.
 

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$750 for a complete roller cam is a very good deal IMO, in fact given that you also got a timing chain in the deal almost makes it too good a deal, much depends on the quality of the cam. I'm not familiar with Engine Works so I cant comment on that, if its all quality stuff you got a very good deal on the cam.

Be certain to find out if the cam requires a special distributor gear, some roller cams (not too many anymore I think) require a bronze gear, most seem to now be able to run a std. or mellonised gear.

You should also have received a cam card with the cam, it tells you how to install the cam and all the lift and duration numbers. It should also tell you the open and closed (seat) pressures required by your valve springs, unless the cam is super tame, you are likely looking at replacing the springs to match the cam specs. .48" lift at the vlave is good for the SR torquer, whose intake flow drops off after .50" Exhaust after .60" .

I agree with the previous comment that if the bearings were through to the copper you want a good machine shop to measure the journals of the crank to determine if it needs grinding, this isnt anything to really worry about. Oversize bearings are available for ground cranks and you see them all the time.

You also want a machine shop to check to see if the bore is good. if the motor is already .040 over and its worn through the bearings it isnt irrational to wonder if the bore is also worn.

Personally I dont like going more than .040 over on a small block, though I have heard of people going as far as .060 - if there is little core shift thats probably ok. If you are lucky you may not need any bore work at all.

I wouldnt worry about identifying the rods. Have the machine shop check them out especially if the bearings were badly worn, if they check out - reuse them. But use new bolts - always use new rod bolts.

your crankshaft: 3941174....307,327...cast....medium journal...3.25" stroke

Unfortunately there isnt enough information to determine potential HP numbers. More important than lift on the cam we need to know intake and exhaust duration, is the .480 lift at the lobe or at the valve? Pistons are they flat top, dome or dish?

good luck and if you are accustomed to working on jet engines then a small block shouldnt be daunting at all, there are a number of good books out there on building the small block, I suggest reading up on it.

Enjoy
 

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Discussion Starter · #9 ·
You should probably replace your valve springs and check them for coil bind at max lift. Any good machine shop can check spring height for you. Start shopping around for a good machine shop. Not the cheapest machine shop, but one with a good reputation and willing to answer your inevitable questions. Good machine work is critical to motor longevity and maximum power. You're going to need block work, crank work, cam bearings, rod resizing, head work and more. There are no shortcuts with machine work...Good Luck
I've got a good one. Basko Engine Services in Gilbert AZ, went through my heads. They worked on a 283 I had a few years back. I trust them.
 

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Discussion Starter · #10 ·
3941174 is the large journal cast crank going by 1 web site,, is the parting line on the crank(stand it straight up) and look at the casting line, its either thin or thick,, if it is a very small thin it is cast and if it is thick your in luck, a rare steel crank,, old truck engine,, good for power, RPM`s,, what size socket did you use to take the rod caps off with?? either a 1/2 or 9/16,, that will also determine a small or large journal,, Matty man

That's intersting. The GM PDF I was just looking at was stating that the p/n's for the block and crank I have are exclusive to passenger vehicles and not the trucks.
 

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Discussion Starter · #11 · (Edited)
$750 for a complete roller cam is a very good deal IMO, in fact given that you also got a timing chain in the deal almost makes it too good a deal, much depends on the quality of the cam. I'm not familiar with Engine Works so I cant comment on that, if its all quality stuff you got a very good deal on the cam.

Be certain to find out if the cam requires a special distributor gear, some roller cams (not too many anymore I think) require a bronze gear, most seem to now be able to run a std. or mellonised gear.

You should also have received a cam card with the cam, it tells you how to install the cam and all the lift and duration numbers. It should also tell you the open and closed (seat) pressures required by your valve springs, unless the cam is super tame, you are likely looking at replacing the springs to match the cam specs. .48" lift at the vlave is good for the SR torquer, whose intake flow drops off after .50" Exhaust after .60" .

I agree with the previous comment that if the bearings were through to the copper you want a good machine shop to measure the journals of the crank to determine if it needs grinding, this isnt anything to really worry about. Oversize bearings are available for ground cranks and you see them all the time.

You also want a machine shop to check to see if the bore is good. if the motor is already .040 over and its worn through the bearings it isnt irrational to wonder if the bore is also worn.

Personally I dont like going more than .040 over on a small block, though I have heard of people going as far as .060 - if there is little core shift thats probably ok. If you are lucky you may not need any bore work at all.

I wouldnt worry about identifying the rods. Have the machine shop check them out especially if the bearings were badly worn, if they check out - reuse them. But use new bolts - always use new rod bolts.

your crankshaft: 3941174....307,327...cast....medium journal...3.25" stroke

Unfortunately there isnt enough information to determine potential HP numbers. More important than lift on the cam we need to know intake and exhaust duration, is the .480 lift at the lobe or at the valve? Pistons are they flat top, dome or dish?

good luck and if you are accustomed to working on jet engines then a small block shouldnt be daunting at all, there are a number of good books out there on building the small block, I suggest reading up on it.

Enjoy
The cam is 480/480. the pistons are dished. If I remember the centerline of the cam is 106-110 maybe?????
 

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Discussion Starter · #16 ·

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L2165 is a trw part number, forged I believe. so good pistons. I dont know what size combustion chambers you have, but a 4 vr piston with any kind of dish will yeild lower CR numbers.

480/480 still doesnt really tell us anything other than the lift at each valve is the same. for a roller cam thats fairly mild. The cam card I posted is the hydraulic roller I use in my smog legal 78 corvette. Because I live in CA it has to still smog. you will notice that it has .480 lift on both valves.

Its the duration that tells us the most. the 106-110 I assume is the intake centerline and not lobe separation. my smog cam has the centerline on 110.
 

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Discussion Starter · #19 ·
Tony,, can you look on the back of motor near the forging # and get the date code?? sholud look like A157.. A=January, 15 is the day and 7 would be 1967,, just an example,, I will goggle the forging # on the crank,, I ground cranks for 6 years,, loved the steel GM cranks,, and if there was no 0.10 or .020 on the bearings sounds like a STD crank,, Matty man
Found the code you were asking about. D158 So I take to mean my motor was born on April 15, 1968??????
 
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