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  #16 (permalink)  
Old 08-29-2012, 10:11 PM
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These guys know more about 389's than I do. I used to fool around a lot with the 400's back in the 70 and early 80's with great sucess. But I can tell you that Pontiacs were known to have weak connecting rods, and it was worth every penny to have the cranks cross drilled and use full groove main bearings. Considering gas today I am thinking you would be building a pump gas motor ? If so keep the compression no more than 10:0 or maybe 10:5 to 1. Lunati used to make some cams that worked extremely well in the 400's. Headers were always a pain in the keester because of the angle of the exhaust manifold bolts, and then you get into the separated Ram Air heads. 400 HP is easily obtainable thou. With a Pontiac you just have to come up with a plan and stick to it. They are not as diverse as SBC, BBC, and some others. You have to know exactly what heads your going to use B4 you buy pistons, and cam, etc. Just make sure you use all forged & balanced rotating assy for the lower end AFTER you decide what heads your going to use. If your choice of heads doesn't already have screw in rocker studs pay the price and get it done ! And for Gods sake don't use the tri power...LOL They were nothing but a fire hazard even back then. I always had great luck with Pontiac motors. But it came with big disappointments at times as well. They are good motors to build as long as you learn thier weakness's first. Bad OEM connecting rods, usually bad OEM cranks, head to piston issues at times, press in rocker studs mostly, and if you can use the Ram Air seprate exhaust port heads opposed to the more conventional 2 inner exhaust side by side ports. Just make sure you can obtain a car that this 389 will work in....LOL Shame to build it and have nothing to put it in....LOL

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  #17 (permalink)  
Old 08-30-2012, 07:28 AM
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The adapters make it so the block will fit, no problem. You're going to bneed the later heads for brackets to all "line up" correctly. There's one bolt "hole" missing in the 389 heads.

Ed, where did you ever "hear" Pontiacs have bad cranks? Simply not so. In fact, the crank is the strongest part of the Pontiac. The block is the "weak link" once the cast rods are disposed of. I don't "fool" with Pontiacs. I build them at the highest level (one 505 has produced over 2,600 HP).

Virtually everything you speak of is obsolete for 20 years now. With the advent of NMCA and muscle car "racing", developement of the ol' Injun has resumed, and they're "back" with a vengance. At the last "Super Chevy" show we attended, the quickest GM-powered car was a Pontiac, not a Chevy. Dirty Bird had them ALL "covered". One of the exhibition cars was a ProMod with an 800" Chevy in it, and a BIG fogger system. We had him by .2 in the 1/8th. There WERE two ProMods with "Brad" motors. They had US covered by about .15. In the competition, Frank Gostalya's GrandAm (540 CID, single 4-bbl., gasoline, no adders) went 7.50s all day,very near 200. The only two Chevys that were quicker had 738 CID and big foggers. They ran 7.40s. Yes, things have changed a LOT
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Old 08-30-2012, 08:55 AM
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The adapters make it so the block will fit, no problem. You're going to need the later heads for brackets to all "line up" correctly. There's one bolt "hole" missing in the 389 heads.

Ed, where did you ever "hear" Pontiacs have bad cranks? Simply not so. In fact, the crank is the strongest part of the Pontiac. The block is the "weak link" once the cast rods are disposed of. Vinny Meyeda of SoCal, runs a 6.90s F/C with a 406 CID Pontiac with a factory nodular crank, spinning to 8,800 every pass. I don't "fool" with Pontiacs. I build them at the highest level (one 505 has produced over 2,600 HP). The 475 in Dirty Bird made 40 passes, shifting @ 9,200, without a single bearing or piston issue. The rod maker says that's all the rods are good for over 2,000 HP. And the same 8 pistons that were in it on the first pass, were in it on the 40th. How many blown/alcohol hemis and BBCs can "say" that, while setting new ET records at the same time? DB was the quickest Pontiac-powered car in the world for nearly 2 years. Still IS the quickest Pontiac "funny", and hasn't been down the track in over a year. The KRE crowd is encroaching, though. Bill Mellot's F/C went a 6.50 at Norwalk earlier this month. We're gonna have to drag it back out and put a "tune" on it, to move the "bar" out further. We'll see what Dave (owner) has in mind. "Catching" the Butler ProMod is going to be a chore, let me tell you! (6.27 @ 22, IIRC)

Virtually everything you speak of is obsolete for some 20 years now. With the advent of NMCA and muscle car "racing", developement of the ol' Injun has resumed, and they're "back" with a vengance. Afterall, can't have muscle car races without GTOs, and can't put Chevy motors in GTOs "just because", so the money flowed and the new parts came forth. Today we have a selection of blocks, heads, cranks, and everything else, that rivals that of BBF and MOPAR. At the last "Super Chevy" show we attended at VMP (2010), the quickest GM-powered car was a Pontiac (engine), not a Chevy. Dirty Bird had them ALL "covered". One of the exhibition cars was a ProMod with an 800" Chevy in it, and a BIG fogger system. We had him by .2 in the 1/8th. There WERE two ProMods with "Brad" motors. They had US covered by about .15. In the competition, Frank Gostalya's GrandAm (540 CID, single 4-bbl., gasoline, no adders) went 7.50s all day,very near 200. The only two Chevys that were quicker had 738 CID and big foggers. They ran 7.40s. Yes, things have changed a LOT coming out of Oakland County... Circle the wagons, boys, it's an INJUN ATTACK!!!

PAX

Jim
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Old 08-30-2012, 11:49 AM
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if you have the room, there's no reason NOT to get a free engine. You'll find a use for it eventually, weather its to put in your car, or maybe horse-trade for something better suited to your application.

Best thing for you to do is follow most of whats been said; ditch the factory rods and use a pair of later heads with the correct chambers for your build. We build stickshift transmissions and the only issue I ever see with a pontiac build aside from the 'speedometer cable goes in the wrong side of the trans' is that SOME people seem to have had an issue with using a crank from an automatic trans equipped car in a motor destined for a manual gearbox. Sometimes the pilot hole in the crank isn't machined properly for the pilot bearing/bushing for the manual trans. This can also crop up in early chevys (283s and 265s) and occasionally we see offshore stroker cranks with a looser bushing/bearing fit than we'd like to see. So make sure you get the correct dimensions and check your pilot hole. It may be easier to use the automatic if the crank needs to be machined to get the manual trans in the equation
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Old 08-30-2012, 07:21 PM
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Quote:
Originally Posted by AutoGear View Post
if you have the room, there's no reason NOT to get a free engine. You'll find a use for it eventually, weather its to put in your car, or maybe horse-trade for something better suited to your application.

Best thing for you to do is follow most of whats been said; ditch the factory rods and use a pair of later heads with the correct chambers for your build. We build stickshift transmissions and the only issue I ever see with a pontiac build aside from the 'speedometer cable goes in the wrong side of the trans' is that SOME people seem to have had an issue with using a crank from an automatic trans equipped car in a motor destined for a manual gearbox. Sometimes the pilot hole in the crank isn't machined properly for the pilot bearing/bushing for the manual trans. This can also crop up in early chevys (283s and 265s) and occasionally we see offshore stroker cranks with a looser bushing/bearing fit than we'd like to see. So make sure you get the correct dimensions and check your pilot hole. It may be easier to use the automatic if the crank needs to be machined to get the manual trans in the equation
The cranks on early (pre-'64) engines aren't correct as-is for TH-type torque converters, either. They need to be machined to accept the TC hub.

I also tend to agree- a free engine is bound to be worth something- if not now, then down the road.
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Old 08-31-2012, 07:14 AM
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We've "heard" of cranks not machined for the pilot bearing (Pontiacs do NOT use a bushing, bearing is NDH #7109), but I've not actually seen one,. The vast majority were machined for the bearing. And he's right, the pre-64 stuff has a bit different "hub" dimensions.

Since it comes in on the "driver's" side in the Pontiac, we always thought the CHEVY cable was on the "wrong" side... (:-

Jim
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