Al2011

Someone is selling a rebuilt olds 350 with #8 heads for $350. They say it has 30,000 miles on it runs strong. The guy said it used to be a diesel olds before but it's converted and comes complete fan to flywheel, oil pan to 4 barrell. Is there a reason why he chose #8 heads for the 350? He said the motor came out of a chevy truck 12 years ago and has been stored covered up in a garage for twelve years but he will start it if i'm serious. Or should I just rebuild my 2 barrell # matching 350 7a heads and that will cost over $2000 when I'm done.

joe_padavano

The diesel-to-gas conversion was common in the 1980s. Mondello used to sell a kit. If the stock diesel pistons were used, the larger chambers of the #8 heads were needed to get a reasonable compression ratio. Other than the extra weight as compared to a gas block, there's no problem with this engine. Of course, the RIGHT thing to do is to buy it then sell at a profit to someone who wants a diesel block to built a race motor.

MDchanic

Nope. Lousy engine. Don't buy it.

By the way, where is the engine and what's the guy's phone number, so I can take it off his hands for scrap?

- Eric

Redog

A 350 diesal converted to gas is actually a 411 stoker, I believe

Look for DX in the block casting

joe_padavano

Uh, no.

All that's required to change an Olds diesel to a gas engine is to remove the intake, injector, and vacuum pump, swap the heads and cam, and install a gasoline engine intake and distributor. I'm not sure how you change the displacement by swapping the heads.

Now, many people use DX blocks to build stroker motors by dropping in the crank from a 425. That's not what we're talking about here.

Al2011

So what do you think about the deal? IS there any pros and cons with this motor? Someone said they used #8 heads for the compression if they kept the diesel pistons. Will my 7a heads work? Should I just rebuild my 72 block?

380 Racer

Also beware the DX has .921 lifters while gas 350s have .842s. Also the DX is heavier than a gas block.

joe_padavano

I would be "someone", and as I posted above, the larger chamber #8 heads were used to yield a compression ratio that can be driven on the street. The smaller chambers in the 7A heads will result in a CR that's too high for normal use.