Hey everybody.
Just your basic engine noob here.
I'm swaping a 327 for the stock 305. Long process so far...
Now, I've been talking to a few people better with engines than I am.
They're saying that with the heads and pistons I have, the compression is approx 12:1. I know the general idea of what that means and everybody's telling me I'm going to have to run racing fuel in it.
I want it to be an everyday car and don't want to run racing fuel in it due to cost.
The heads are the old 2.02 "double hump" heads. the block is bored .060 over and it has high rise pistons in it. That's about all I can tell you.
Can it run on just premium or would it just be bennificial to get new heads to lower the compression. if so, what would you all suggest?
thanks

 

You could get away with heavily retarding the timing and running premium. MY buddy used do cruise a big block 427 (bored and stuff) on the street with almost 13.5:1 and he retarded the timing and used premium and the 104 Octane boost. But this wasn't and everyday car. I run a tad over 11:1 in my small block and I have NO problems with good grade premium gas, infact mine runs better on regular 93 octane then it does with race gas.

If it is TRULY going to be an everyday car, I would suggest changing the pistons or heads. But that will be more money you will need to shell out, or like I said run premium and retard the timing BUT you will foul out plugs very easily.

 

Yeah, moneys kind of a problem (the reason i don't want to run racing fuel) but I was thinking of maybe selling the heads and just buying different ones. exploring options/looking for ideas from people who know their s**t

 

you can probably get some cash for those heads. Try ebay, someone wanting #'s matching parts maybe...Then buy some bigger chamber ones.

That, or use cheap flat top TRW hyper pistons. Say $140 for the set. That'll lower your CR. Depending on cam, you probably want 9.5:1 CR. Despite what others here say they've run, you say you're a noob, so better safe then sorry right? Higher the CR, the more you have to be extra extra careful with the tune. Besides, dropping half a point in CR gives you safety, and you lose, what, 6HP? 'nuff said.

 

speaking of cams, how do you tell what kind of cam you have? Nobody I know, knows a thing about cams.
When I bought the engine, the guy told me that I bought the engine from told me they rebuilt it, threw it in an old monte carlo and then swapped it for a big block.
After tearing it apart, we think it came out of a race buggy (popular up here, i don't know if it is anywhere else) so I'm assuming the cam isn't stock.

 

If they're double-humps WITH the bolt holes (186, 492, 292, 041), people will pay a pretty penny for them. If they're the older ones WITHOUT the holes (461, 291, etc.), they're nearly worthless; because there's alot more of them in the world than there are cars that can use them with owners that want to go that route.

Getting the pop-ups out and putting in flat-tops is the only really good long-term solution.

If all you want to do is just get it back on the road and you don't care about wringing every last HP out of it, or even getting very close, just jam a pair of cheeep un-worked-up 882s or similar 76cc smogger crap on it; and save up your pennies for building something better another day.

 

any markings on the cam? front face have a part # stamped?
That's definately a good thing to think about while rebuilding the motor, what cam is in it

 

HP would be sweet but at this point, I want to get it done before winter.
Well, ya see, about rebuilding it, It was rebuilt recently. It was supposed to be a "pull out and drop in" job, but we tore it apart just to make sure everything was up to snuff. and it wasn't. The crank needs to be replaced. and the guy left the original oil pump in it but put a high volume oil pan on it
I don't know for sure if anything is stamped on the cam. It's sitting 20 miles away in my friends garage. Next time i go up, i'll take a peek

 

Doesn't matter if it was rebuilt yesterday and never run; if it's an unworkable combo, it's an unworkable combo.

Get the numbers, if any, off the top of the pistons. That will help determine for sure what you've really got, and therefore, what to do. Same for the cam. Whatever you see on either the front or the back end of it might be a clue.

 

It did run before I got it...i never saw it run but it has been run.
Thanks for the info. I should be going up sometime this week to paint under the hood and i'll be sure to write the numbers down.
until then, thanks

 

I went up yesterday. I didn't have time to pull the cam but on the top of the piston it just says ".060" On the bottom, they say "D 13 99"
that help any?