Compression

[J.Prock]

How high of compression ratio could I run with 91 octane with out detonation? Is like 11:1 too much?

[Leeperryracing]

if you have aluminum heads and a decent fuel system, 11:1 is fine on 91 octane...just don't get carried away with the timing.

[J.Prock]

I have cast inro heads so 10:1 would probably be more appropriate for my engine?

[Leeperryracing]

with iron heads, 10:1 is about max for a "street" car if you wanna be comfortable on 91 octane...there are a ton of iron-headed 13-15:1 motors out there but those are max effort race motors running on C16 or alcohol/methanol.

[J.Prock]

I'll just see what happens I guess I am getting my motor in this week so I'll see what they say I wasnt empressed with it last time I ran it at bandimere best it ran was 15.5 which is slower then the TPI but the timing was set at 40*! and that caused it to eat up the bearings... I'll keep everyone informed thank you tho!

[Leeperryracing]

40* total timing shouldn't "eat up" bearings unless you don't have adequate bearing clearances or you were getting detonation and you didn't know....low oil press/oil starvation WILL kill bearings. Who builds your motors?

[J.Prock]

I bought the motor from a guy who pulled it from a chevelle it was just rebuild when I bought it and we got it in. Ever since we drove it it never ran like it should only ran a 15.5 best et which is slower then my 120000 mile tpi. Also over the few weeks we drove it oil pressure started dropping started off it would run like 40 psi when warm and ended up at like 15 psi when warm (which is probably from the bearings wearing down). Hopefully it isnt an expensive problem. but we will see

[Mark Wells]

If you have not changed your oil yet, drain it and check for debris in the drain pan and in the filter.

[J.Prock]

We took it in today to get it taken apart to see what it was I know when we drained the oil just before pulling it again is was full of metal and little chunks really a pain that we had to pull it out so soon after putting it in but I guess thats life... lol

[J.Prock]

Well looks like i need to save up the motor I bought of craigslist was junk they took it down it spun two bearrings but worst of all aparentally the machine work on the block was HORRIBLE so bad the block is trash. What a waste of money on the motor. IDK what to do now looks like the old girl might be going back stock engine but I have no clue.

[Mark Wells]

That really Sucks!!! I would tear down and re-check anything I purchased from someone else (unless I knew him/her). It sucks getting burned even worse when money is involved. Guarantee whoever assembled it knew it would not last long....unless they were idiots and did not use plastigage....Hell they were idiots either way!

[J.Prock]

LOL thats for sure! I went down and saw it and aparently it spun EVERY main bearing one was even worn down to the copper! Looks like Im going to have alot of parts for sale soon like heads intake carb etc etc

Next week my old TPI is going in do be taken down and have them go through it make sure nothing is wrong with it and maybe have it rebuilt.

[Mark Wells]

What part are you going to have rebuilt? The TPI parts should only need new gaskets and a through cleaning. If the heads are good you can use them on what ever block you go with 305 or 350. You can pick up a used 350 for $100 to $300 that needs to be rebuilt. If only the bottom end got thrashed the rest should still be good, rods and pistons at least. I have seen rebuild kits for SBC 350 for $200.00 through Summit Racing (2 piece rear main).

[J.Prock]

I think I'm going to get the whole motor rebuilt I saved the orignal 5.7 in the barn but it has 120,000miles on it. I was going to reuse the world heads off of my 355 but they are different would that edlebrok base allow me to still use? Or should I just say forget them and stick with L98 heads (what are better?)

[86IrocZmidnight]

It all depends on what you want to accomplish. Building an engine can be costly.... I did a budget build; lower end completely redone and re used my old heads and I am in to mine about 1200 and that is reusing the water pump (and I did take that apart and check it over.) But I had machine work done at the tune of over 300, that was a crank turn, block tanking, cylinder bored, polishing and resizing. The expensive part was the engine kit (500) for complete gaskets, rod bearings, mains, high volume oil pump, molly rings, steel freeze plugs and hyper-utetic cermaic coated flat top pistons.

Heads can enhance or smother your block. You can pick up a good used running motor as a temporary fix for around 400. I had that option, but went a different way.

Just my two cents.

[J.Prock]

Well I already have some money saved up in my car fund for when I was going to get my car painted so I can get get the engine work done. Plus I have my jeep so I have a vehicle alittle down time wont hurt . What is really going to suck is redoing all the wires for TPI. I am thinking about just going for it and buying a new harness from painless to make it easier and get new wires in there to replace any old ones.