True...gotta watch for the 1/4" difference in crank snout length. Not completely sure of the year they made this change but I believe it was '64. Just measure while you have your crank out {of your engine}.. I know some guys have skirted this problem by whipping up some spacers that install behind the pulleys and behind the accessory mount brackets...no big deal.. Nice thread, Axle. And it seems a lot of other guys have some very helpful knowledge too. I'm happy to see a renewed interest in things Pontiac. I usta run 55-57 Pontiac 2 doors with 59-60 Pontiac 389s. I'd drive the 55 chevy guys [with 283s and 327s] nuts. It was fun to watch their eyes as the "old man's car" would motor past them. I know some guys have had sucess with the 57-63 automatic transmissions, be they "hydramatics" or slimjims. Personally, I never liked the way they shifted or the huge ratio differences between 1st and 2nd gear. I've always gone with a 58-60 stick Bellhousings and run Muncie 4 speeds however the 56 hardtop in the photos used the early 4 speed, slant-pan hydro and a 60, 389 engine. They work together IF you grind a bevel on the crank flange so the engine-half of the fluid coupler sits flat against the crank flange's flat surface. If you forget this detail, the coupling will leak all the fluid out and the wobble will take out the tranny's front pump in 3.68 seconds after starting the engine. The claim that the late 50's and early 60s Pontiac axle shafts were 29 splines is true but the same year Olds are 31 spline. The 57-58 Olds axles fit in 57-58 Pontiac housings and allow you to use the 59-64 Pontiac posi 3rd members. Pontiac axle shafts after 58 are all wider than Olds of the same year because of the famous "wide-trac-ride" pontiac offered....screwed us all up if we wanted to use the heavy duty 59-up rearends in our narrow ford/chevy hotrods. Again, nice thread, alex. These great engines are finally getting the recognition they deserve. If you don't think these engines are powerful, just attend the annual the POCI convention, complete with drags....many 9 and 10 second doorslamers and 6 and 7 second dedicated race cars.
That would be the correct manifold for the year. I suppose someone could have swapped it in at some point in the past. I'm not sure what you mean by your last statement...are you asking if there's supposed to be a VIN stamped on the intake? That 0378276 XY you gave earlier was stamped on the front of the block, yes? I believe that should be the only place the VIN shows up on the engine.
I figured it out, I was expecting a big long engine code, not just an XY...Thanks for your help guys...It appears my motor is a '76 400 170hp motor, thanks guys...oh, and I got it mounted in the car today with my custom made mounts...
Stamped block codes appear first in mid-59, all in the same place on the right cylinder bank. But they're never more than 3 or 4 characters tops. That's also when the serial number was added. The early ones can be pretty shaky, or else the '60 I have the number was stamped on by some backyard mechanic. But it does match the car serial number.
6X heads were made from 1976-1979 and either had a #4 or a #8 as a secondary number for chamber size. 350 and the 220 hp 400s got the #4 secondary code and the standard 400s got the #8s These numbers are on the lower part of the AC cast pad. 6Xs are the same castings as the 5Cs of 1975. 1979 used the left over 400 blocks from 1978 and only came in 4 sp Firebirds, Olds 403 and Chevys came in the autos. Pontiac blocks and heads are very well documented as you can tell the date and hour that they were made.
I agree, I also never met to sound like your wrong, I'm right. Pontiac did alot of stuff that the higher ups back then and some also to this day say was never made. Case in point. Arnie Beswick said when he took delivery of his 1964 GTO that would eventually become the "Mystery Tornado" it came equipped with an aluminum front end. The Factory said that they never made such a thing. Arnie eventually gave the front end to a guy that was helping the crew at the time because he went to a fiberglass front end. The guy put it on his '64 GTO driver and got into a wreck with it and it was destroyed. Cool stories and a cool thread!!!!
Yes Groucho, Thats him. He has just about maxed out with his Iron block and is now thinking of going with an all new forged steel block and aluminum heads so he can break in to the mid 5's. I remember going to street races or even legal drag races in the 1980's and being the red headed step child because i drove a pontiac. There was only a few people out there...at least in my part of southern California. The only serious parts guys i remember were Warrior,Nunzi, and H-O Racing Specialties. Back then, if someone was to tell me where the industry would take aftermarket Pontiac parts in this day & age i'd never believe it. I personally think the biggest improvement in technology has been with Cams,heads,intakes.
I was under the impression that Pontiac used Powerglides in 53 and some 54 cars due to the Livonia MI hydramatic fire. Those Pontiacs had 6 and straight 8 engines, not till 55 did Pontiac have a V8. So I surely would like to know who had Dynaflows in their cars that were originally equipped with such.
Here's a quick one for when your cruising the wrecking yards or swap meets. All performance heads with big valves had screw in rocker studs, the small valve heads used press in rocker studs.
That would apply to the muscle-car era engines; I don't think any motor got screw-in studs until the advent of the first Super Duty; maybe even later than that.
I bought a friends 77 TA he had drag raced for a number years for the front subframe, M/C, 400, trans and rear end. Welding in the front end under the 55 was easier than trying to unf__k his pulley arrangement. My understanding from other Pontiac guys (this is my first) is that the pulleys can become a pain in the ass when trading around parts. He had used shims and washers and tubing that it was a complete nightmare to disassemble, especially at the track quickly because he was always throwing belts. To prevent this in the future I simply inserted a spacer. Now the belts are aligned.
HOLT CRAP! the HAMB is PSYCIC! I swear, last night Dad and I fired up the poncho that came in the 50 chevy! Nuthin' brings a smile like firing a v8 with open headers at 7pm She was hitting on all 8, no smoke, and had oil pressure, so good to go. I was just researching what I've got sitting there. YB block, '75 bird, 2brl 145 hp, 7.6:1 with 89cc heads #13 heads, '70 400"s, 72cc. That should give me 8.8:1, not to shabby. Should be ok with the edelbrock torker intake. Anything else I should watch for (besides a 2-4brl intake )?
I did this, worked like a charm AND prolly drove Rockola nutso. Worked like a charm.......now to finish painting the beastie. DESOTO is RIGHT. Just because heads and manifolds bolt up, does NOT mean that they will work. When I built my 60 389, I needed heads and exhaust manifolds. I could had used earlier stuff, but WHY waste the money trying to get them opened up? It was simpler and smarter to just find the correct heads.
When swapping the good 67-70 high compression heads or most heads onto a 62-66 engine be aware those engines used shorter pushrods and headbolts. 8.687" vs 9.125". I dont remember the exact differane on the headbolts, but when I put the 670's on the 66 389 for the 55 I had to use the longer 400 headbolts. I bored it out to a 400, but the valve reliefs are differant on those pistons, if keeping the 389 pistons and using 400 heads, keeping it under .500 lift should be safe.
Very important. Somewhere in the mid 60's the valve angle was changed and the appropriate pistons must be used. Because of this, most cheapie aftermarket pistons have EIGHT eyebrow reliefs so they'll work with any heads/valve angle. Not too good if you're building a hot rod Pontiac for flame travel/compression. OONGAPOTCH is what those pistons look like
"I did this, worked like a charm AND prolly drove Rockola nutso. Worked like a charm.......now to finish painting the beastie." Yeah, and now everyone knows why I'm like I am... Good thread Axle....I'll bet ya didn't realize it would generate so much interest.
Yep, it's always safe to double check it with clay too. I decided when I built mine 10 years ago, since I already had the heads done. It was cheaper to get forged 400 pistions than cast 389's. It got the heavy trw's than , now I would have gotton alot lighter piston and some good forged rods. It's a good time to have a Pontiac, especially so many good aftermarket parts are available.
Cool thread.......I picked this up a few years ago. 1959 Pontiac 389, hilborn injected, vertex mag, complete from a vintage sprint car. I'm hoping to put into a model A pickup project. I've been in a local GTO club since the mid 80's so love Pontiacs too! All the guys I know have had motors done by Dave Bisschop @ SD Performance in BC, Canada. His high end motors run low 9's and many street engines that run 10's-11's-12's, and don't miss a beat. First class guy and first class products and services. http://www.sdperformance.com/
Good Pontiac info.First time on the hamb.I have 56 316 with bad rocker studs.I want to install screw in studs 7/16 style.Can I run later rockers that came with 7/16 stud.Originals rockers used 3/8 stud with no oil hole at pushrod tip.Also this engine came out of gmc truck.It has dish top pistons.I have been told truck 316 had lower compression than the car version.Any input would be great help.
No the late Rockers will not work on the early heads, early '55~'60 heads have a different valve angle than the later '61~UP heads. Your rockers are shorter than the later ones, You need to replace the studs with the CORRECT Pontiac service parts for the early head. You may be able to run the larger stud size, but it wont be a straight forward swap.... Will prolly have to modify the rockers & use POSI~NUTS to adjust the valves.
Rockers or PUSHRODS are different length? I might guess you can use the screw in studs as mentioned earlier in another post. BUT, use hollow pushrods (of the correct length) to get the oil the old studs provided. Also, the different valve angle shouldn't affect the rocker arm, but piston reliefs being in the wrong place. But, that's if you change heads, not rockers
Yes Groucho (& Minty), The ROCKER ARMS are shorter on the '55~'60 Pontiac DUE to the different valve angle. You forget i have the EARLY stuff & have gone this this shit before. The Rockers are SHORT compared to the later ones.. NOT interchangable !!! The tip of the valve is CLOSER to the stud due to the VALVE ANGLE. He needs to get EARLY screw in studs that have the oiling holes if ya want to oil the rockers correctly, I have heard of guys drilling the rocker & useing hollow push rods. But if ya use the correct EARLY parts you dont have to screw around. ALSO, Only '55~'57 heads can be used on the early block due to WATER passages, So dont get froggy & put LATER head on it.. You will only cause MORE problems
I think you're talkin rocker ratio(distance from valve tip to stud), not valve angle. Two completely different things. I doubt they changed the ratio. I think 1.5's a standard ratio. "BUT" you do have more experience in pre 60 Ponchos. Maybe I'm sniffin glue over here.
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