OK I took out the crank and wow thing looked NEW, it was cast though. I just had to share the pic of the piston! I'm not an expert but can I say very little run time! Honestly I cleaned the top and top 2 areas above oil ring THAT's IT...notice though, on the rod there looks to be something hit it.
So I was able to free it up and tapped out the pistons. Damn, cylinders below area where there is surface rust is so nice too.
Any recommendations? Rods will be replaced but should I find another 400 block and use these pistons or go another (try) +.030 so total is +.060. I'm leaning to find a short block and use these pistons.
The guy I bought my 68 from has a Pontiac 400 that's the light blue color looks like OE iron heads the OE 4 barrel intake (air gapish). Its a long block that IS SEIZED, engine is together with chrome valve covers. The guy asked me for 300...Isn't that a bit much for a seized engine? I thought value is more like 150 tops 200.
Before I turn it down on a period correct engine, thought I'd ask experts and before I regret turning it down later.
My plan is to use a LSx but don't want to ignore a period correct engine. I could always use the EFI carb on it.
Thoughts?? What's the cast number I'd look for?
11-18-2013 10:08 AM
I just junked a '67 400 and a '69 428 in the past two years that were not seized but would have needed sleeves. A seized block, unless it's a rare code for your numbers matching car, is scrap iron value the rest of the time. $300 will buy you a decent rebuildable 4oo core that turns, maybe even runs. There's a good running later 400 with the TH400 trans for sale on the other forum for $500. I wouldn't pay $10 for a seized engine....I don't need the scrap money that bad for the labor involved taking it to the recyclers.
11-18-2013 10:10 AM
Even if the block is seized the heads and the intake should be good, and worth $300. The crank might even be useable. Then if the block is salvageable it's a win-win. If it still had the original Quadrajet even better, but you mentioned it has an EFI carb? Which is also great. Everything will need rebuild, mind you, but if you got on ebay and tried to find a set of 68 GTO heads you would probably spend more than $300, and an intake would be $85-$125. If the block turns out to be junk you can find another bare block and use as many parts from the original engine as possible. LS swaps are nice but the reason so many Pontiac people keep the Pontiac engines is that they're just so damn good!! It's one of the few engines that can put out significantly more torque than horsepower, the cranks are absolutely bulletproof, the heads and intake are some of the best flowing, and quadrajets once tuned properly are nearly comparable to fuel injection. That being said, there are plenty of other great options, and an LS swap is one of them.
11-18-2013 12:04 PM
I think 300 is a bit much. Too many factors. So it does seem like these blocks are not so rare? No EFI carb on it, just a plan. I would rather lean into this than a LS1 swap just because its cheaper right now. I'll offer the guy less and see, will try 150. Thanks
11-18-2013 03:19 PM
Is it the right block for your car? Or another year/car model? These Pontiac engines bolt right in to your '68 GTO, and if you do the math, have more torque and power than an LS1. If the engine is seized because of rust in the cylinders, it's probably junk. BTDT many times.
11-18-2013 09:41 PM
Thanks, please correct me I thought these older iron blocks can be bored a good amount. I agree, I just don't know. So my question then becomes whats the max bore I can go?
I was told it was rebuilt once, so yeah there can be a good chance block is junk.
On the LS1 fact, I average 400+ on my H/C builds and my Pace Car 408LS3 is 520/500 RHP/TQ so I thought about putting this in the goat with a better drivable cam. Really though, I would lean more towards the 400 Pont. Cost point is much better with the 400 without the wiring needed.
11-18-2013 10:15 PM
You can easily get 500hp and 530+ torque out of a 400 Pontiac engine if you wanna build a 461 Stroker motor. Bear would be the man to talk to regarding such a build as far as cost, builders, parts, etc.
.060" is max overbore for a 400. Not much, if it's pitted in the bores due to seizure.
11-19-2013 04:24 PM
We dealed down to 200 for the 400, so now I have a 68 and a 400. The cast on the block is 9799914, so its a 70 400. Don't know what the heads are yet since I looked at it once. I pray it isn't too bad inside. I want to keep it original looking with some mods. I'd like to get 500hp out of it.
I've done some research and don't understand why 9.5cr seems to be the edge for pump gas. I have 11.2 on my 408LS3 and did 10.4 on my Ford 347. I'd at least shoot for 10.5 with the stock heads. Honestly, I've never messed with Iron heads and from what I read there is tons of CC volume to mill depending on code.
I have much to learn but I do have enough knowledge to understand what and why.
11-19-2013 05:15 PM
If it's a numbers matching 70 the heads will either be #12's or #13's, unless you stumbled upon a Ram Air IV engine, which is unlikely. If it was you would also have an aluminum intake.
If you want 500hp out of a 400 the best approach is a stroker kit. Like I mentioned earlier, Bear has a 400 built into a 461 stroker with Edelbrock heads and is running over 500hp and under a 12 second 1/4 mile. Talk to him if you think you'll go that route.
Static compression does not determine whether you can run on pump gas or not, dynamic compression does. If your car is running at 10.5:1 static comression ratio, the dynamic compression will likely be below 9.5:1, which will run on pump gas. Read this PY forum thread. It might help with understanding a little: static vs. dynamic compression ratio - PY Online Forums
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