I hope there is an early pontiac expert who can answer a few questions. Can i use chevy rockers? Do later pontiac 400 pistons, rod and main bearings, oil pump and valve springs fit? The later parts are easier and cheaper to get hold of in the UK. The alternative is getting a later engine complete but will the block mounted starter work with my flex plate and will it all mate to my hydramatic? Please help keep a pontiac in a pontiac... Ian.
You might be able to use the 400 pistons with around a .055 overbore - the 370 is the same bore as the 389 - but it has a shorter stroke and smaller rod and main journals. The oil pump will interchange. Someone else will have to handle the rocker question, and I'm looking at my Motors and seeing the springs get taller as they get newer (installed height) which probably means differences in the valves too. Keep in mind that you could bolt up an entire late top end to your block, too. But Kanter should have the engine parts if no one else does, I would think they'd ship to the UK, you might check with them - If you were to use a 1959-1960 389 block, they have the same stroke as the 400 and the same size mains and will bolt to your trans. A block with the starter ear has a different bellhousing bolt pattern - you'd have to put a short tail TH350, TH400, or 200R4 in with it. I gather you haven't had the motor and trans out of the car, or you'd be able to see why the late motor and early trans wouldn't work together.
Try www.BOPengineering.com www.egge.com Pontiac rockers are different than Chevy. Oil pumps will interchange with a 400...Egge carries a rebuild kit.
repoman should be able to tell you more, and if you join the pontiac-1950s e-mail list at yahoogroups there's a couple of good tech guys on there too -
Steel crank, perfect r/s ratio, beefy block. The 370 is one of those rare 'perfect' motors. Problems are bellhousing, starter, and oil pump. 557 HP @7000 rpm using ported iron heads. PM me for my email and I'll give you details on the build. I have my notes and specs. My goal is to get a set of 400+ cfm heads on top of one of these and make it live @ 11.5K rpm for more than a second before it runs out of oil. The Pontiac oiling system leaves much to be desired at the upper limit, but 8500 rpm on the street with 2-bolt mains is a walk in the park for a 370 or 317. I spent several months doing research for this project. I had help from some Pontiac veterans. There are a few unique tricks for this short block. You can make your own starter mount without too much trouble. You need to reuse your oil pump housing, and use gears from a Melling MD54D late oil pump. You need to carefully choose your bearings. Two types are available, China, and USA tri-metal. I have a source for you. Chevy rockers don't fit, but sb Ford does. Best to throw those 58 heads in the bin though. Use 67-70 closed chamber big valve heads with a late model timing cover. Wilcap can sell you a trans adapter to use a modern trans for @ $300. However, the early hydros bolt up, and are great transmissions with 4 speeds. Of course, you may want to keep it simpler, lol! I can help. It's a great motor whichever way you want to build it. First step is a sonic check. 428 Pistons drop in @ 4.120 bore using common 6.8 chevy mountain-motor rods, and a bit of machine work. Stock bore is same as a 389/400 @ 4.0625
repoman - Sent you a PM with my email and cell. I'm interested in the details of your build, as I am close to going through my 370 again. Anyone else done a 370 lately? I've picked up a tip recently on better front and rear seals, and am looking for any additional insights to take into consideration while everything is going back together. Thanks.
I'm actually wanting to swap out the intake , distributor and possibly the heads with a later model version if possible. Can't remember what actually interchanges on the top end with those 370's. 389? 421? Anyone?
PY forums,best bet.I have chevy 152 rockers on 60 pont heads.3/8 chevy studs. No run yet but I could not find any differance on valve opening or alignment, rocker to valve tip.
Ian Do you still have your 58 Pontiac 370 engine? Is it for sale? Regards Charles- Real Steel 01895 440505
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