I have never owned a BBC but if I ever decided to *visit* the darkside then I'd need to know some stuff... a lot of stuff. I have a million questions but I'll only ask a few at a time. First, take the GMPP 454 crate engine for example, Its a 4.25" bore and 4.0" stroke and has 8.75CR with 118cc combustion chambers. According to an engine compression calculator the deck height would be .009" to get this 8.75". That means that the piston is almost flush with the deck. So a 100cc head would yield me 10:1. Correct?

64cc seems to be one of the most common cc's for aftermarket SBC heads. What is it for BBC heads?

I have 195cc runners on my SBC heads, what does that equate to in the BBC head world?

What cc intake runner would be on the edge of being too small for a BBC for the street. What cc would be on the edge of too big?

What are considered good flow #'s @ .400lift for BBC heads?

Cams! I have a 228/235 .530lift 106LSA cam, does all of that cross over into the BBC world or would it be entirely different numbers? Would a 106LSA be just as lumpy in the BBC or do they use different LSAs? Same question for duration and lift...

Thats all for now.... they'll be more.:)

Shawn,
Quick notes...

The GMPP crate 454's have too low of compression unless you want to use forced induction. You are on the right track looking at compression. A low compression BBC will be stout, but they run better with good compression.

Larger cubes will tame the cam specs. A 228/235 duration cam in a 454 would be a nice cruiser cam, the 106 LSA will make it lope but that cam would fall off at about 5500-5800 in a 454.

Oval port heads fall into the 240-290 cc range for intake runner, this is a good goal for a street or mild strip motor. I wouldn't use anything larger than a small rectangular port (305-310) on a 454.

Common chamber size is 118cc.

Yea I know the 8.75 kinda sucks, because not only is it not 10:1 (pump gas friendly) compression, its probably too high for a blower. I was just using its specs as a baseline for info. I wouldn't have made it my engine choice. It was the easiest complete 454 with available info to use for my CR questions.

Oval or rectangle... is one preferred over the other? Are both style intakes the same price and readily available from ...say Edelbrock? I can look all of this stuff up, but I figure if someone loves to talk about Big Blocks and knows there stuff... this site would be easier to learn than searching for hours...

How about stock ratio rockers... are they still 1.5 like the SBC's?

What degree heads are considered most widely used... Example --23* heads for SBC

I'm sure I will wear out my welcome with subject but SBCs are all I've ever known... sorry.

Oval or rectangle... is one preferred over the other? Are both style intakes the same price and readily available from ...say Edelbrock? I can look all of this stuff up, but I figure if someone loves to talk about Big Blocks and knows there stuff... this site would be easier to learn than searching for hours...

How about stock ratio rockers... are they still 1.5 like the SBC's?


The rocker ratio for big blocks is 1.7, but they make 1.8 (like the 1.6 for sbc)

Here are my edy heads before and after I had some work done to them. They have been called roval, because they are in between.

http://i31.photobucket.com/albums/c392/imtheflash/new%20heads/intakerunner2.jpg

http://i31.photobucket.com/albums/c392/imtheflash/new%20heads/newhead4.jpg

It looks like someone who had the GMMP 454 crate engine, wanted a torquey street car, and wanted close to 10:1CR would benefit best from the 290cc Eddy head with the 110cc chambers or the TrickFlow 280cc heads with the 113cc chambers.