And Guys both my son and I have 383 lt1's, his in a 95 bird and mine in a 96 vette and they are awsome both are mid 11 second cars.
But we recently built a 509 for a buddy that he put in a 68 camaro with a turbo 400 stall and 373 gears. I had the pleasure of driving it at our local track it's first time there. I made a couple of passes just to get the feel of the launch letting off about half way down. Then I made one hard pass, Imagine the owners eyes when the track officials came over and asked us to leave.

MR. OCCIFER SAID AND I QUOTE
NOW BOYS YOU KNOW WE CAN"T ! HAVE 10 SECOND CARS RUNNING HERE WITHOUT A CAGE!!!!!!

As much as I love my corvette
NOTHING AND I MEAN NOTHING FEELS LIKE A BIG BLOCK
sucking you back into the seat. This is what inspired us to build ours and stick it this old 69 camaro thats been setting out back for 10 years.

GOOD LUCK AND HAVE FUN!!!!!!

 

Thanks for all the info timebandit. Let me know when you get your engine built, i'd like to hear the results!
So you were only charged 300 for the complete 454 tall deck engine? or was that only the block?
4.35 bore is .60 over?

 

Hey Krucible check this out it won't last long the price it right.

http://cgi.ebay.com/ebaymotors/ws/eB...category=33615

this is a 540 cube monster with all the goodies being sold for 5k but it will need a cam. it only has 4 to 6 hrs on it and the guy has 12k invested check it out. this is a steal

Also we paid 300 for the complete motor

 

Time,
You are right, that is a good deal. However, one of the reasons I want to build this engine is as a learning experience, so I can come more familiar with everything.
I appreciate the thought though.
Jason

 

Krucible the are some good books on the big block chevy that will help a lot.

How to Hotrod Big block Chevys by Bill Fisher and Reb Waar

This book covers all the Gen IV blocks and most of the combos you can make with it up to a point. Since it was written about 10 years ago it doesn't cover some of the modern stroker combo's.
But it is excellent on covering the details of building a big block including how to blue print one even down to blue printing an oil pump, head porting etc.

There is also another one out for the Gen V and VI engines.

 

what would you guys consider to be a "safe" dynamic compression ratio for a BBC with iron heads? Same for aluminum heads.

 

Big Block Chevy's are a little more complicated. The thing is that a 12:1 427 with standard type heads (not small chamber race heads) will with most small cams have a big problem with street gas. Where we can run that in a LT1 with a big enough cam everyday (due to the lower DCR)

While the 427 will have problems the 572 might not. Alot of it has to due with the piston and chamber shape. The big dome piston that would be needed on a 427 to get 12:1 is a big reeason you can't run as much static compression on that engine. You'll also probably use smaller duration cams on top of that compared to a 572, so in all it's not just one thing but alot of them since big blocks have such a big range of displacements. In turn having alot of displacements acting on the same size combustion chambers, therefore vasty different piston domes to create the same compression ratio.

One more thing, say you were trying to build a 468 BBC that wanted to run max compression ratio on street gas. If you are looking to get 12:1+ (in turn around 8.9:1DCR) you are faced with alot of things to get proper burn and not have detonation. The problem is that the standard good flowing combustion chmabers are around 118cc and can really only get dnwn to 100-104cc range when they get milled. Now you need a decent size dome to make up for those big chambers. This is where bore and stroke come into play on a BBC. Dome height is a problem on a BBC since any dome does not give optimial burn speed, therefore more timing and tendency to detonate. The only way to lower the height of the dome and take up that same amount of volume for your compression is to spread the dome out. That's how bore vs stroke plays into that. A larger bore gives you more area to spread the dome volume out into and in turn gives you a more optimal piston shape and theoretically the ability to have higher SCR and DCR.

So the answer is it depends. Cubes, cam, chamber shape, dome shape etc... all play into the max DCR and SCR you can run on any motor, especially a BBC. Obviously a iron head will like less than a aluminum version.

That's all I have from vaction right now.

Bret

 

timebandit,
i have heard with 454t blocks you have a very limited selection of intake manifolds (only single plane). what are you using, if i may ask?

 

Here are some guidelines that work well for us and have proven to be what is run on many street and race engines.

This is assuming that you know how to properly calculate effective compression ratio. which I assume is what you are talking about since dynamic compression has to take into account volumetric efficiency and is very hard to calculate.

For pump gas engines an effective compression ratio of 7.5 to 8:1 is generally accepted as giving good results.

Hot street engines and 4 valve engines can be on the high side of 8:1 up to around 8.3:1

Race gas engines are typically between 8.5 to 9:1 max.

Again these are just ballpark figures and should not be considered absolute values, just a way of getting close for your combination.
If you follow the cam manufacturers recomendations on compression it will usually keep you in the safe zone. Most of the catalog cams from Comp will put you in the 7.5:1 effective compression range which will be safe for pumpgas. Some aluminum heads may allow you to push the limits a little higher but I would still recommend staying closer to the safe limits.

 

You sure you want to say that Dano?

I interchange some terms now and then, which is not bad because they mean the same thing.

Bret

 

oh wow, i was under the impression 10.5 to 1 was going to be okay. :/

 

Im not sure you understand what you were asking. What you are calling dynamic compression is figured by calculating the position of the piston in the bore when the intake valve closes and comparing that volume to the volume left above the piston at TDC.
The reason people look at this is to get a ballpark idea at what compression to use for their cam and application. For what you are doing you should probably not worry about that and just build your engine to have the compression recommended by the cam manufacturer when you figure out the rpm range you want to operate in and pick a cam to fit that range.

 

I guess to the average person on here it wont make much difference what you call it.

There is a difference though between mechanical compression, effective compression, and dynamic compression. But I think some people like to throw around terms like that on here without actually knowing what they mean.

 

Krucible

We use a brodix single plane drilled for injectors but there are several manufacturers that make intakes for the tall block.

Brodix, World products, etc

They are not by any means hard to find. We found ours at a car show in memphis.

 

Venting.

You know what else has been really bugging me?

The way people have come up with so many different abbreviations for Lobe separation.

LSA, LDA, LCA . Why do we need so many different ways to refer to the same thing?

Thats all.