Can I use an LT4 short block that is zero deck, none milled (they are ported) LT1 heads and a 306 cam without running into any issues?

Anyone think the CR would be too high for pump gas or even piston~valve clearance?

 

Never hurts to check the clearance just in case!

 

True, But I was hoping someone might know before he buys the shortblock and then finds out he needs to go to a smaller cam or worst has to tear the block apart to prep if for cometic gaskets to get the clearance he needs.

If I'm figuring it out right, looks like about 11.8:1 compression? Seems a bit high for pump gas?

 

11.8 isn't too much with the right tune and good gas. I can't see why it won't work. I think the only cam clearance problems are with strokers. I was told the PTV clearance had more to do with the duration of the cam that with the milling/decking of material, and that small cam should be fine.

 

Not really, the cam is going to bleed off some of that compression.

 

do some research into static and dynamic compression

 

I am zero decked and run the CC306 w/ 1.6 rockers and stock heads.
No clearance issues. The 11.8 compression is a little high for me, I wish I was around 11.0 instead.

I was dyno tuned in 65* weather on 91 octane. I can drive the car all around on 91 except for the summer months here. I can get away with short trips at night, but thats about it. This is in AZ though, temps get 100+.

I considered getting a cockpit adjustable timing retard, but for now, my car just hibernates 5 months out of the year.

However, my little 353ci puts up nice numbers for having unported stock heads.

 

Yes it does!

 

Sounds like your tuner was a little too agressive on the timing, you should get it dyno tuned in the summer, 11.8:1 should be no problem with the 306.

 

Well, yeah, I could pull timing and it wouldn't detonate. It would also kill my horsepower.

I only put 1500 miles a year on the car, it can sit in the garage for the summer. If it was my daily driver, I could easily make tuning changes and it would be drivable year round. Of course I would have to get a BeCool as well.

 

You'll gain power pulling timing vs pinging, and when I had a mail order tune I got dyno tuned and my tuner ended up pulling 5 degrees of timing out and I gained 30rwtq at 3000rpm's.

 

If I chose to drive my car in the heat, I would do that.

 

Fireman and doesn't like the heat. I like that.

 

Post is a little confusing...If he is purchasing a shortblock, there would be no heads on the motor and therefore, relatively easy to check piston-to-valve clearence, C.R. etc. and would also not be an issue to then install a thicker head gasket if necessary. Don't mean to pick apart your post, maybe I missed something.

 

He's looking at a complete LT4 / 383 shortblock that is already assembled and using his heads ( ported, but not sure if they are milled ) and Cam that were on his stock block, he lost oil pressure and killed the bearings.

He is on a tight budget, was going to do a budget 355 when this 383 turned up. He already has started collecting gaskets and such, has the .029 head gaskets ect.

My concern was if he found out he has clearance problems or too high a compression for pump gasket after be bought and the engine he'd be stuck with a none running car and no money.

I'm thinking that even if the clearnce is good he may still need to get the intake machined to realign the ports. That he can factor into his budget. But not having the piston to valve clearance and having to sends the heads and block out to be surfaced for thicker cometic gaskets, get the pistons notched or changed etc, these cost more money they just taking his stock block and building a 355 that is in his budget.

So I was hoping someone here could tell me yes/no/maybe if they are running something the same. My block was decked and I have milled heads. The builder told my up front cleanace would be close so the surface was preped before he shipped it. I did have to spend the $200+ for commetic gaskets to get the clearance I needed. So I just want to check before he gets in over his budget.

JB