Today I am very excited, I have found a complete 5.8 engine I am looking at purchasing to go into my truck. Hopefully I can go and take a look at it soon. Does anyone know what a 351 engine should have for compression BRAND NEW? I believe this one has somewere around 55-70k miles but I would just like to compare compression to a new engine. Also, the guy that is selling it says it has 150psi with no variation between cylinders. Is this good? Thanks a bunch guys.

 

That is very low mileage for a 351 so it should be in very good shape if it was not abused. 140-150psi is excellent, but seeing is believing, have the owner demonstrate it for you and see it for yourself.

Also you did not mention what it came out of. If it is from a passenger car such as a Crown Vic you might want to consider a different cam, if it is from a truck already then you should be fine. Just be careful if you are fuel injected because speed density systems on stock trucks are sensitive to duration changes in cam profiles.

 

yes, very good, but like fast pony said, seeing is believing so i would test the compression to make sure the guy isnt lying or anything.

 

150psi is good but when doing a compression test the most important thing is that there isn't a big difference between cylinders. If they are all around the same then you know the rings are good. If the engine is still in a vehicle ask him to hear it run, thats the most important thing, make sure it doesn't knock or anything. If the engine only has ~75K on it, it should be in good shape.

-Jon

 

I bought the 351. It came out of a 97 F-350 so it is the more valuable roller block. Anyone know if it has a roller CAM in it? I hear so much oposition about this. It has 64K on it and has everything except flywheel, accessories, and computer. It was already removed from the wrecked truck so I didn't have the option of hearing it or testing compression. It actualy came off ebay from a company who deals with used engines. Now I must decide if I am to go MAF or stay speed density and stick with a milder cam. Any suggestions?

 

If you have a roller block, that means it has roller lifters and a hardened lobe roller cam. The bosses in the lifter valley are higher and this is what allows the use of the taller stock roller lifters. Also the distributor drive gear must be a steel gear to work with the roller cam as it's gear is hardened, so if you plan on swapping distributors, don't use a bronze gear, it will eat it for lunch.

As far as what to do, that depends on what you want and what you are going to put this thing in. You can stay with injection with the right combo or go carbed if installing in an older truck.

It really depends on what you ultimately want, once you decide how far you want to go and much you are willing to spend, then we can help you out much better.