[SCREAMIN400]

What are the exact differences between the early V8s and the later ones? I know they changed the direction of the coolant flow, but thats about it. Can anyone enlighten me? I was reading a thread where someone couldnt put a
'60 intake on a '63 389 and started to wonder.

[1955SC]

Early V8's '55- 60 used a different timing cover and water pump, and the ports between the intake and heads are a different layout. My understanding is that if you take the heads and intake as a set they will bolt to any block.
Camshafts will interchange between all pontiac engines.

[SCREAMIN400]

Alright schweet. I was a little worried there for a minute. I started looking into the '55-'57s thinking I could apply some old hot rodding magic to the 287-347 and then was worried I wouldnt be able to. Thanks.

[Bill Hanlon]

55-56 2.5" mains
57-58 2.625" mains
59 and later 3" or 3.25" mains

Oil pans particular to 55-58 and 59 & later.

Camshafts MAY be interchangable physically, but the engines that provided oil to the rocker arm balls through the rocker studs (62 and earlier and I think some later 326 V8s) must have the cam drilled to provide the oil via #2 and #4 cam journals. Some do, some don't.

Oil pumps from 59 and later installed on 58 and earlier engines will hit the crankshaft.

59 and earlier use a single front motor mount that attaches to the bottom of the cast iron timing cover. Later engines with aluminum timing covers will probably not be able to hold up to the vibration. Custom mounts required.

The length of the crank snout changed in the early-mid 60's which effects which harmonic balancer you use.

The stuff below is something I saved from Rick Gonser a few years back.

INTAKE MANIFOLDS ARE MATCHED TO PONTIAC V8 CYL HEAD DESIGNS IN THE FOLLOWING FASHION: 1955-57, 1958-60, 1961-64 AND 1965-79 THESE ARE OFTEN REFERRED TO AS TYPES I, II, III AND IV. THE DIFFERENCES ARE TWO-FOLD, i.e. WATER FLOW AND INTAKE BOLT PATTERN. TYPES I AND III HAVE SIX BOLTS/SIDE TYPES II AND IV HAVE FIVE BOLTS/SIDE WATER FLOW IS A FUNCTION OF WATERPUMP HOUSING, INTAKE MANIFOLD, AND CYLINDER HEAD. IT IS POSSIBLE TO INTERCHANGE BETWEEN/AMONG TYPES, BUT THAT DISCUSSION IS TOO LENGTHLY FOR THIS REPLY... A TYPE I TRI-POWER (1957) WILL FIT ANY 1955-57 CYL HEAD. THE TYPE I IS UNIQUE, IN HAVING THREE SMALL ROCHESTER 2GCs. IT WAS THE ONLY YEAR THAT SMALL ROCHESTERS WERE USED ON THE ENDS. BECAUSE OF THIS "UNIQUENESS", THE TYPE I COMMANDS HIGH PRICES, AND IS RELATIVELY HARD TO COME BY... EDELBROCK AND OFFENHAUSER MADE AFTERMARKET MANIFOLDS WHICH WILL WORK ON TYPE I, II AND III HEADS. THE EDELBROCK IS CALLED THE P22, AND THE OFFENHAUSER IS CALLED THE EP SOMETHING OR OTHER. THE OFFY IS STILL AVAILABLE NEW, AND CAN BE ORDERED WITH PROVISIONS FOR EITHER SMALL CARBs, OR LARGE CARBs... HOPE THIS HELPS! RICK GONSER SR TECHNICAL ADVISOR POCI TRI-POWER SPECIALIST

[SCREAMIN400]

Where do you have to drill the cam? Can the average machine shop do it?

[Bill Hanlon]

I don't know where it has to be drilled, just that it is in the #2 and #4 journal. Oil enters through the cam bearing, goes through the cam and exits through the other side of the cam bearing. One of the journals supplies oil to a gallery that exits the top left side of the block, through the head gasket and into the head gallery which the bottom of the studs also enter. Hole in the stud passes oil to the ball of the rocker. Same thing happens through the other journal to the right side of the block.

Many Pontiac cams are drilled even though the mid-60's and newer don't use the hole.

I assume a decent machine shop could do the job if your cam wasn't drilled, but I do not know if the hole goes straight through the middle.

I'll bet Pontiac Jack will sign on tonight with more info.

[Jack Gifford]

No, not a straight-through drilling. It's two drillings that meet in the center. I'd need to go look to tell you the angle between them- I only remember that it's not a nice 120 degrees that you might expect at first glance- which is why you need to be careful when installing the bearings. However, it's a moot point- most of us wouldn't employ the through-the-studs oiling anyway.

Bill- Any idea what '57/58 difference was referred to in your post above? I've swapped back and forth between '57/58 heads, and don't recall any differences at all. And, of course, I've never forgotten anything, ever!

[Bill Hanlon]

Originally Posted by pontiac jack

Bill- Any idea what '57/58 difference was referred to in your post above? I've swapped back and forth between '57/58 heads, and don't recall any differences at all. And, of course, I've never forgotten anything, ever!

I'm just echoing Rick on the heads. Casting # is definately different 57 to 58. Different part # for valves & head gaskets as well.

I bought a set of rebuilt '58 heads from a machine shop in Wyoming via eBay. When they arrived one had been dropped and had cracked. Insurance covered my costs for both heads, but I only was required to return one. I still have it in the garage if you know anyone in the Houston area who needs one '58 head. It has been modified with ARP screw in studs, oil-hole type rockers, after market valve seals and guide plates for the pushrods. Free if you come and get it.

[SCREAMIN400]

Originally Posted by pontiac jack

No, not a straight-through drilling. It's two drillings that meet in the center. I'd need to go look to tell you the angle between them- I only remember that it's not a nice 120 degrees that you might expect at first glance- which is why you need to be careful when installing the bearings. However, it's a moot point- most of us wouldn't employ the through-the-studs oiling anyway.

Bill- Any idea what '57/58 difference was referred to in your post above? I've swapped back and forth between '57/58 heads, and don't recall any differences at all. And, of course, I've never forgotten anything, ever!

Can you change the oiling so that its not through the studs?

[Jack Gifford]

Yes, simply change to rocker arms that have the oil hole above the pushrod. You can plug the feed holes in the block decks if you want, but it's not necessary. That said, a word of caution- 'Pontiac' rocker arms don't work on '55-58 heads, as the dimensions are different. So changing to rockers with oil holes is 'simple' on '59-'63(?). For '55-58, there are a couple of options-
1) Have a machine shop drill and deburr oil holes in the original rockers (pushrod cup is extremely hard).
2) Scrounge for SBC rocker arms with oil holes, checking for correct geometry on the Pontiac heads. I've done this successfully, but didn't pay attention to exactly what year SBC they came from.

[tom s]

Jack,when I did my alu 389 which was a 59 patern head with oil thur studs ,I used Comp roller tips and they worked fine.FYI,Tom

[Jack Gifford]

Tom- that's what I would have expected on the '59-pattern heads. It's the '58 & earlier that use a shorter rocker arm.