Taking a poll...351w overbore

Cheapsnake · #1 (**permalink**) 03-30-2005, 08:55 AM

I recently picked up a 351w long block that was built by a shop in Montana. The block was supposed to be .030 over, but when I opened it up it was .060 over. I contacted the seller (not the shop that built it) and we're in discussion now on how to resolve this.
I got a real good deal on the engine with a lot of goodies that went along with it, so I don't necessarily want to turn my nose up on the .060. The block is a D4, which is supposed to beefier than the later years so I suppose that should make me feel better, but with little experience in these engines, I hate to rely on my own gut.
So, I'm posing the question to the forum, especially you 351'rs out there, would you be comfortable going .060 on this engine. BTW, I'm planning on 375-400 HP, NA out of the engine. It'll be used as a weekend cruiser, with an occasional cheap thrill. Thanks for any opinions.

blykins · #2 (**permalink**) 03-30-2005, 11:05 AM

I wouldn't see any problem with it. I have a D9 block with .060" overbore. Running 10.5:1 compression....pushing 485hp....haven't a bit of problem out of it. Knock on cast iron.

I'd run it.....

grego37 · #3 (**permalink**) 03-30-2005, 12:37 PM

Are you going to run it at .060 over, or are you going to rebuild and bore it to the next size?

351w are usually thick enough to go that far, but personally I wouldnt chance it. What happens when you want to rebuild it , are you going .080 over?

On any block going past .030 I get it sonic tested, This process tells you exactally how thick each cylinder is and if its safe to go to the next bore size.

I'd find a nice std. bore block and bore it to .030.
and when you want to rebuild it down the road you can go to .040 and so on.....

Cheapsnake · #4 (**permalink**) 03-30-2005, 01:38 PM

Good point, .060 is the end of the line for this engine. I suppose I would just scrap the block if it ever needed another rebuild.

lovehamr · #5 (**permalink**) 03-30-2005, 03:31 PM

Have it sonic checked before any reboring. Most reputable shops can do this and it could save you a world of hurt.
Steve

Jack21 · #6 (**permalink**) 03-30-2005, 03:56 PM

If it's a running engine, and you plan on putting the engine in the car without any further cylinder work, fine.

If you intend to register the car using this engine, D4='74, the car should be emissions exempt, and you may be able to obtain Classic Vehicle, or Antique Vehicle tags for it.

The block cannot be overbored any further. Next rebop, it's time for a new block. Old Windsor motors are relatively plentyful, and reasonably priced, even if you have to buy the entire car just for the motor.

Bruce Edwards · #7 (**permalink**) 03-30-2005, 07:19 PM

One other thing that can be done is sleeve it bac down to standard and start over. If it is .60 over now and has been run for several thousand miles it will not be round in the bore area any more which means you will not get the rings to seal and or it will be over sized when you hone it and you may get piston slap.
If your heart is really set on this block and it is worn at .60 you'll have to sleeve it to save it.
Or as others said get another block.