I am purchasing an Olds diesel and am wondering what the best route is to build a budget bullet proof gas motor. The engine has never been in a vehicle as it was donated by GM to a vocational technology program. When the program was discontinued, my friend bought the engine at scrap price. It only saw approximately 50 hours run/dyno time and still has the injector pump, intake, heads and exhaust manifolds. Should be run some SB Olds heads like #8's? Any advice on lifters, intake, crank, etc. Is appreciated.

 

If it's not intended for an all out race piece, use the block and the crank......maybe the rods. But keep this in mind.....there's a bunch of machine work ($$$$$$$) that goes into the conversion from diesel to gasoline. Then there's the availability (or should I say LACK of availability) of other stuff........pistons, lifters, assorted other valve train pieces. Other than cutlassfi on here, good stuff is big $$ and hard to source. There's no such thing as a "budget" build with a diesel starting point. Ask yourself this BEFORE you embark on a DX project.......what do you want to accomplish or do with this thing, how much $$$$ do you have to spend, do you have a time frame you're working under for completion. Might be a better plan to look at a build based on an early (68/69) 350 gas engine (with either the early iron heads or alums if you can swing the $$), or if you want more inches, then a 425. Consider obtaining the DX (if the price is pennies on the dollar), then sell it off for a few bucks to put toward a 350 or 425 build. As an aside........my blown DX has more than 2.5 times in cost to build than a gasoline 350. Not an expert, just an Olds guy who has learned what and how much it takes.

 

Figure out where you’re going with your build. As mentioned above, it can get expensive. My short block wasn’t overly expensive but with how conservative it is built and what is now available, I could do it with a gas 350 block & Mark’s stroker kit. Block is lighter, crank is lighter, although my bob weight was only 1777. The “abnormal” expense in my build was crank work w/ 425 piece and bushing the lifter bores. SBO crank kit would require spacers which trades to even money. I think Mark has a crank available with the bigger mains for the conversion which would save $$. The diesel crank is fine if you’re staying at 350ish cubes. I did put 2 bolt forged caps in mine, primarily because when I disassembled the core, one of the caps was broken in 2, although the engine didn’t seem to notice it. Once you see what lifters are in that engine, you’ll know where you stand on that subject. The injector boss area requires some minor machining. Other than those items, the rest of it is no different from a gas block.

Personally, I wouldn’t consider running anything but one of the aluminum heads available, or soon to be. #8’s would be the dead last choice, even if using Iron heads.

If you’re going mild, I would consider selling the diesel whole, that would be a cool engine for someone to use as is and might make a good start or cover a stroker kit and core block. If you’re gonna get serious, that diesel block makes a great foundation.

Some of the builders will hopefully contribute here soon.

​​​​​​….

 

"budget"
"bullet proof"
"olds"

Pick Two. Also really, really depends on what you mean by "bullet proof". 1000hp? 2000hp?

As for the gas conversion, there's extremely LITTLE machine work. Use an angle grinder to cut back the injection pump boss so you can use a standard timing chain. If you're using the stock crank then you're done! You just need to plug the hole in the back of the intake valley (old diesel return line) and either use a standard cam bearing in #1, or plug the oil pass-though if you use a back grooved cam bearing.

In dead stock form the block is probably good to ~600hp? I won't make any wagers on the stock crank and rods though. I think Trovato claimed he would go close to 800hp on the stock short block when talking to V8TV about the build he did for them.

You can get steel caps from Dick Miller, then line bore and hone. Around $1200-$1500 all in. Usually convert to studs while doing this.
You might be able to get 4 bolt caps from Trovato or Stolpa. Getting the side bolt holes drilled will cost extra of course.

Lifters are probably the biggest ordeal. You can stick with stock lifters if staying mild enough. Going any more special then, well.... The adventure begins.
You can see if Mark Remmel has any more of his SBO Stroker 3" mains cranks left. They use an LS rod.

 

Great stuff! Thanks!

 

And in case anyone comes looking - I never found this documented anywhere, just had to buy a pile of freeze plugs until I found the right one - the freeze plug for the back of the intake on a diesel block is: (drumroll)
45/64", Dorman 555-082

 

That is good info that may help keep a few people from scratching their head. Crazy fraction, for fun I converted it in case it seemed to have been metric - 17.86mm. Oh well.

 

I’m pretty sure that Freeze plug comes in the Melling kit that I buy, BR-124.

 

Well, I bought the complete engine today. The exhaust manifolds still look new. I will be parting out many items. Are the stock pistons worth using?

 

Subscribing

 

I’d sell everything besides the block to get some cash to do a stroker build or you could keep the diesel crank and keep it stock stroke or have it offset ground. If you want my opinion, I’d go with one of Cutlassefi’s cranks it isn’t cheap but it saves on time, machine work and is a new piece all ready to go. You don’t need 4 bolt mains on these blocks for even a nasty street build. I have a set of 2 bolt billet BTR caps on one of my blocks and I’ll guarantee it handles 800hp no problem. Find yourself some decent forged rods and pistons. It won’t be cheap overall but it will be bulletproof for a nice street setup.