I may have an 5.7lt Oldsmobile engine and trans, 1974 Diesel, auto trans. Have been told that engine can be changed to gasoline by changing the heads. Anybody know anything about this setup? Thanks Patrick
As a diesel they are not a great motor. Prone to cracking heads between the valves and popping the top off head bolts. Grade 8 Caterpillar bolts fixes the latter of those problems. Supposed to be a strong bottom end to base a petrol motor on though. If you just changed the heads the compression ratio would likely be too high. I stand to be corrected. The DX blocks are the best ones to use. DX will be on the side of the block. I think the DX's were a later block. There used to be a news board for enthusiasts of these motors. Try searching under 350 Diesel. cheers.
You mentioned something about a 1974? This engine was not made until 1978, which was the 260 cubic inch form. Stay away from these early blocks, I concurr with the "DX" stamping, these will be 1981 and later designs. This upgrade included roller lifters, which only appeared on the diesel engine. You may have a clearance issue with the injector pump drive flange and the intake??? Cylinders heads would obviously have to go, as far as the bottom end is concerned, the DX blocks had larger beefier crankshafts and connecting rods. All engines had forged free floating pistons. What are you using this engine in? If it is a truck, why not do something different and put the whole running engine in there. Hell, back in the day these road oilers got 28-30 MPG. Ford 429 rear oil seal replaces the shitty rope seal that always leaked. BTW, Back in the day I had a shop that specialized in diesels, worked on more than I want to remember. Seems my customers that used the vehicle for it's intended purpose(ie...travelling salesman) had the least amount of problems. Wish I knew about the CAT headbolts back then. Used to be able to slide a head off and back on in less than 2 hours. (cha-ching $$) If you find out more info about the diesel to gas conversion could you please PM me. JT
When I was in college, one of the "jobs" we had was rebuilding a whole bunch of them 350 Diesels. When we pulled the heads off, we found damn near every one had cracks between the valves in the head casting. Funny thing is, it was in "spec" to rebuild them that way. There is a forum for them on the Delphi boards (I don't remember the site, a Google search should find it) or try gm-diesel.com. DX blocks are what most people look for, they are beefier. Jay
i want one of those engines,a running one if possible,for my shop truck. i had several of those back in the day,my wife drove caddys to work when she was 22 years old,nobody could figure out how we could afford to drive a caddy! hahaa! randy
you can do it but you MUST use the gas rods and pistons,the best street combonation would be a flat top piston and 5a heads would give you about 9.7 to 1.We tried this setup in a dirt car but used the big cc 403 heads with copper head gaskets the diesel rods and shaved diesel pistons,the second time the motor hit 6,200rpm all eight rods streached and hit the heads. if you do end up using the deisel rods stay below 5,500rpm,all in all a strong touqer defintley a good setup for a heavy ride or just good burnouts.
DX build-up example wanna see small blocks in the 600-800hp range naturally aspirated, build with a dx block. go to that site and search around.
http://www.442.com/oldsfaq/oldsfaq.htm Check this site out..it talks about all the olds engines made (or most). It talks about the DX blocks also, they has forged cranks supposibly.. but the blocks are heavy duty with lots of nickel if i recall which serve well for a high hp engine. even if im wrong..the correct info is at this link.
I fatfingered the original post, should have been a 1984 year engine which makes more sense after reading the posts. Thanks for all the replys and info. May look into making this up into something to put in my 41 Dodge PU. Thanks again . Patrick
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