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Old 11-10-2013, 07:38 AM
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what's the diff.?

What's the diff between a 400 pont. 481988 block and 9799914 ? Is there a problem with either one fitting in the 76f/bird ? Thanks

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Old 11-10-2013, 08:17 AM
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I have an old AERA cylinder head and block id manual, and according to that, the 481988 is a Ponch 400 that was used from70-76. The 9799914 number is a big block chevy 400 (aka 402) used from70-72. There is however a 400 Ponch with a number of 979914 (one less 9) that was used from 70-74.

What motor did you originally have in the car? Ponch or Chevy? I know for a few years there, GM was mixing and matching. Either way, I believe it is just a matter of different motor mounts to switch brands. Not sure if there is room for a big block chevy in that body, but the Poncho blocks are pretty big too, so if they fit, a BB Chev probably would too.
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Old 11-10-2013, 08:55 AM
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Thanks, I found a website w/pon #'s and it listed the 9799914 as a RA 3 with 4 bolt so I thought it was a pont # ,It could be my mistake or the w/site but I was wondering if diff in HP between #'s .I know the 4 bolt is built stronger for more HP .My 76 is all pont. I'll have to look for the ad again to make sure .
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Old 11-10-2013, 10:40 AM
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IIRC all the 71-76 blocks had 5 pads for motor mount bolts. And they were all drilled and tapped. Check to be certain that this is correct. Check the bosses that the F bird mounts use and compare that against your other block . That would be the only Issue that comes to mind as far as interchange is concerned.
Heads may or may not have bolt holes in the end exhaust ports for manifolds or headers . Depending on which heads you have. Be sure to check heads for accessory bolt holes also.
Fact is stranger than Fiction
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Old 11-11-2013, 04:52 PM
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The "914" casting is pretty rare. It IS a 400 Pontiac, as well as a BBC. IIRC, 914 is the '70 Ram Air block. If so, yes, it will "fit" in your later F-body. Some had the number fully "cast in". Others had the last three digits ground off and the 914 "stamped" in (factory). There must be 5 mounting holes drilled and tapped on each side of the block (as Lynn said). The date code is on the top by the distributor. Alpha-numeric, 4 digits. It looks like a "tag" but is cast in. The first digit is a letter. The next three, numbers. Same as Chevy and other GM castings. The letter indicates the month (A = Jan, B= Feb, etc.). "I" is not used. The second and third numbers are the day of the month. The last number is the last digit of the year it was cast. Example: A109 would be Jan 10, 1969. It COULD be Jan 10, '59 or '79, but they didn't make the same blocks in those years. Deduction brings you to the correct date. Dates coded after July 7 (or so), are next year's model. In those days, they would shut down during the week of 4th of July to "retool".

If it has only two mounting holes, it's a '67-'69 block. Not all is "lost". Ames Performance sells adapters to use the earlier block in the later body. Not too "hokey", either.

If it is a '70 Ram Air block, get the engine code. Unless you're planning a MONSTER, that block is much more valuable to the collector crowd, and you could sell it, buy a 988 plus a few other goodies. A true "WW" ('70 Ram Air IV, manual trans) block is worth a couple grand if "usable". A "WS" is a popular code as well (Ram Air III, manual trans).

What are your plans? You don't NEED 4-bolt mains until HP passes about 650. Even then, it's debatable. We have many 455s "out there" with 2-bolt caps and factory bolts making 600 and living. 400 blocks are tougher. I like them a LOT better. We have one man with a 455 in a 3,200 lb. GTO going 9.80s with 670 heads (iron, d-port). The thing is a torque ANIMAL. The front wheels come up about 3' when it leaves. He's making more like 700, and probably near that in torque. It cracks a main bulkhead about every 60 passes or so. He considers a "new" block maintainence, not repair. We're starting on a new one using a 400 with "splayed" caps and an Eagle forging. He should be able to make a couple hundred passes before any trouble may start. Going to "more" cam, too. He wants lower 9s.

We (Lynn [LATECH], Bill Creech, myself, and others here) can steer you in the right direction regarding the Pontiac. It's a whole different beast than a Chevy, so bear that in mind when gathering data. We don't "do" them the same as we did 5 years ago, much less 25... 400 Pontiac has proven to be among the best of ALL the muscle car era powerplants. Modern goodies make it run just as "good" as any other older design using modern stuff. And "real" connecting rods are now available cheap. DO NOT consider using the stock rods. Even a 2-bbl. gas mizer should get forged rods...


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