This should be simple... By '77, did the Pontiac 400 still have a provision for the pilot bearing to run a manual trans behind one? I know you could get them that way in a Trans Am, but I can't remember if 77 or 78 was the last year they actually cast up a Pontiac bigger than a 301. It occurs to me debating what to use in my A pickup, I have one sitting here, a 400 out of a '77 Gran Prix. I bought it cheap to go in my '57 Pontiac that I've never done anything with. This thing is a 180 horse emissions motor, so weak I think I could probably run a T5 behind it without killing it (maybe, it does have 325 ft-lbs torque). If I could come up with a set of heads that would bump the compression up to like 9:1 or 9.5:1 I might mess with it, but I forget what number heads I need I just remember that they're hard to find. It aught to make a 2500-lb pickup go pretty good, even so. The motor's buried under a bunch of other **** in the garage, so it's hard to go look at it. But if I ran that in the A, I have a couple of bellhousings that should fit, mounts are simple, and I even have a ratty set of headers to fit D-port Pontiac that could go on it. There's a set of M/T valve covers out in the garage somewhere and a set of '60's chrome covers too. That's been the problem so far, finding an easy, cheap combo that lets me run a V8 and a manual trans - eerything I have that runs I need to get a manual setup for or I need to put the motor together ('57 Plymouth 301). I might be able to scare up a Studebaker manual, where I got this from there's a Lark that they tried to move when the ground was frozen - so I can see in the carc*** a manual, but I need to cut brush and move some heavy steel **** to get under the hood and see if it's a V8. (I know a guy who has a decent '57 or '58 stude V8, apart and protected, under a bench in his barn, I can probably trade Packard stuff for). The other goal is to keep the horsepower reasonable both for fuel economy and to avoid stressing the frame a whole lot.
Every 400 crank I've seen so far has been drilled for the pilot bearing (bushing), but if by chance it isn't, any 326, 350, or 389 crank will fit, which gives you a much larger pool to chose from. Pontiac went to their last bellhousing pattern in '61 (with a block mounted starter), and this was adopted by Olds, Buick and Cad later on in the 60s. Most or all stick bellhousings will have dual starter cutouts and will bolt to all the 60s and 70s style GM stick transmissions and from what I 've read, the Camaro T5s up to 91 or so. All D port heads 65 up have the same bolt and port patterns and will interchange, however in 67 the valve angle was changed and the valve reliefs in the pistons need to match the heads. The 67 067 heads were closed chamber, 68 and later heads were open chamber. The early 70s publications by HO Specialties cover this topic of head ID and desirablity as well as and probably better than most anything else written about it. That said, a camshaft change is probably the quickest way to start waking one of these motors up. Last motors were cast and built in late 77 or early 78 and the last 400 motors were saved for 79 model year TransAm and Formula Firebirds with 4 speeds only, (the automatic cars were all 403 Olds motored and had 6.6 Liter callouts on their hoodscoops),
The last (real) Pontiac was cast in '78. They used leftover motors for 79 Trans Ams. Not all cranks were fully machined for the bushing if it was an automatic. There is no hard rule for this, some were, some weren't. You have to take a look. It's a cheap job at the machinist. The motor you have is a very low compression 400, but it is a torquey motor that will move an A pretty good. the heads flow well, they still had the big intake valves, and screw-in studs. If you want to get them shaved, a full point of compression is easy. The motor also has a tiny cam. Putting early 72cc heads will give you @10.5:1 compression, but the little cam will make it ping like crazy. The heads to look for are 70's 350 heads, with castings 6X, 15, or 4X. But it has to be off a 350, these same numbers were on 400s and 455s with big chambers. The 350 heads have a small '4' cast into the thin riser on the side of the head. I'll take a pic later. The question is; How much work do you want to do? 350 heads will be a nice boost to the performance. A mild cam will make a big difference. Early 60's heads, and a cam will make it a monster.
Fosho and repoman are right on the money. As for heads, you have a few choices. 80ccs will get you 9.34:1. 90ccs will get you 8.6 (which is not near as bad as it sounds) Here are some heads to look for: #64 #94 #96 #7K3 #4X (3H) #4X (7H) #46 #6X (4) The numbers in parentheses are a small stamped # on the flat machined surface just under the valve cover rail. This # tells which combustion chamber cc your casting has. For example, some 4X heads have a stamped 7H whick means 96cc. Some have a stamped 1H which are 115cc. Yea, lots of stuff to know to find the heads you need, but on the good side, none of these heads are "rare". They should all be cheap and easy to find. Holler if you need anything, -Abone. try this link for casting #/cc decodeing. http://www.angelfire.com/on/geebjen/heads.html This is the top secret ultra-bad*** cylinder head guide. Lots of popups though..
Say, I have a 69 or 70 400 with a bad crank. But I also have a good 389 crank. So I can use the 389 crank in the 400 block? Is this a drop in and go deal? Josh
Same journal size, same stroke. There may be a slight difference in balance, but it'll bolt in and run.
I probably should clarify, I know my way around Pontiacs fairly well, I rebuilt a '59 389 in college. When I bought this motor, all I cared was that it was a runner, I'd intended to stick a 200R4 behind it in the '57. Plus, by the end they were so low powered that I never paid a whole lot of attention to detail. 389 crank is the same stroke and same size journals as far as that goes. Might want to line-hone the mains before you swap it, but I'm sure some of the experts will have better input here. By the way, the Pontiac went to the BOP pattern in '65, there is an adaptor sold to mate 61-64 engines to later transmissions. The bolt pattern is close, but there is no place to mount the starter. I could have bought a pair of 4X's that were pretty clean last weekend, the guy will probably have them at the next car show, but they were loose - the additional ID will help me figure out if they're useful. What I thought my smartest move would be is to get a running motor and sort out the trans combo, so that once I get the frame ready I can throw the engine in and go with it. Then once I've driven it some if I'm not happy with it I can mess with it. I used to run a '60 with a 389 with a 2-barrel and that car would go like stink. Now if I could just find a fairly decent '58 Pontiac dash.... By the way, Repoman, when you thinking on picking up those '56 blocks? I haven't even taken the heads off the one I pulled out of the car -
One thing that nobody has touched on is the 1977 &up crankshafts have a smaller 2&1/2 inch regester for the flywheel most ponchos were 2&3/4 inch good luck finding a flywheel it took me 2 months of constant searching to unearth one! But if you decide to run a 389 crank I have a flywheel for that, let me know.
6x's and 670's are getting harder to find, but they are still out there. I have seen the t-5 behind a couple of these motors, but the end result usually isn't very pretty. better to go with a stout 4, or a built 5 speed. a stocker will let go in a relatively short amount of time. if you have difficulty finding a flywheel,I have a source. and let me know what you are thinking about for heads-I have a shelf full of good ones. I will have another set on monday or tuesday as well ( but I forget what casting they are...) the ram air 4 cam is a killer, but if you are gonna back it up with a t5, get ready to pick up some parts. (like off the ground)
I figured that. Thanks for all the advice - I still think my smartest move is to run the motor as-is until I get the thing drivable and can run it a while. My other option sitting here is a '60 283 HP 389, in the car, like 106K, still turns over and should run. I have a couple of 4-barrel intakes for it, but with the two that's on it now I could run a neat Stude side-barrel air cleaner I think. I drove that car with the stock hydramatic for a long time, I wouldn't touch a thing on it - it hauled *** in a 4000-lb car with a 3.08 gear, it aught to make a Model A about break the sound barrier. The only thing I think is better on the 400 is with 7.6:1 compression I can run cheap gas in it. The problem with the '60 motor is finding a 58-60 manual bell. For a reasonable price. I have a '56 bell here that I went ahead and sold because it's too small for most late transmissions, and the 55-57 manual or anything else that fits up I'll break in a hurry. I had a line on one here that got sold and I had a line on one in Rochester, but the catch was you had to buy a complete '59 motor and trans combo for like $600 - I just didn't have the money to blow at the time.
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