coppercutlass

so according to the btr olds book running bbo heads on a small block is like running ported sb heads. Now i dont know how much truth there is to that and i know i can run aluminums but i can probably get some bbo heads cheaper and just do a vlave job, mill them and call it a day that is just a thought. I have a 355 that needs very little to be completed i got from a fellow forum member. I was thinking of building it as a nice back up. runing a milder cam than what i have now but taking of advatage of the added air flow the bbo heads have to offer. I know most people say j heads are junk which i would assume that would be on a bbo build but how would the stack up on an sbo. I know i will need an rpm intake to port match to the bbo head. Possibly bulding this as a nitrous motor with a milder cam for better street driving and just doing a 125-150 shot for the track.

MDchanic

Just remember that with the larger tracts you'll lose some charge velocity and midrange torque, and that, of course, once they're milled enough you'll have to start from scratch to figure out the pushrod length.

- Eric

coppercutlass

I figure if i match the pad height from my current small block heads to the big blocks if it's possible i might be able to retain my current comp push rods. i figure even if i went aluminum heads i would have to mill them as well. it would also be a trade off i think on the higher rpm with the nitrous it would be good as far as air flow goes . I really want to build another engine like the first one i had with a mild cam good street manners and enough power on the street to have some fun then at the track crack the bottle open and let her eat. My new engine is going to need a 3000 stall and driving on the street with that soggy shift is no fun. Im going to enjoy this new build i have but the next one im going a whole diffrent direction.

DoubleV

BBO heads will flow more air because they have bigger ports but will kill velocity on a smaller engine so it will feel soggy until you get your RPM's up. BBO heads on a SBO is a good swap if you are building a high RPM screamer where you want to flow as much volume as possible up top. They are not the best choice for milder builds.

I think people say the J heads are junk because they don't flow as well on the exhaust side in stock form as the earlier heads do. They're like the SBO 8 heads in that regard. Porting fixes that and puts them on par with the ealier heads.

So I'm no expert but it doesn't sound like BBO heads on your build is a good idea.

coppercutlass

milder on the street but will turn rpms at the track with nitrous thats where my trade off is . my current 6 heads have been re worked pocket ported and all that good stuff but have been milled to make 10 to 1 compression on a near stock deck height. If not i think im just going to get another set of heads for this build . i want good street driving manners and performance on the street dont mean a thing to me i just like a snappy shift and reliable driveability. At the track thats a diffrent story.

DoubleV

Well if you want to get rid of those 6 heads, I might be interested.

captjim

You don't NEED high rpm with nitrous, just the opposite. I ran 12.7 shifting at 4800 with a 100 shot. Nitrous makes it's power down low.

A decent converter will NOT be sloppy. It will drive fine with minimal slippage then stall at WOT.

380 Racer

Copper.......I would listen to Jim if I were you.

captjim

Now you are just being ridiculous....

coppercutlass

I am listening ., essentially im shooting for what he did . I know a decent converter wont slip alot. i just want stock like driveability. My current combo should run right where i want to be at e.t. wise on the motor which i think might be around what you ran on nitrous. Once i get what i want from this engine im going to something more tame so i can run nitrous . Since i dont run every weekend i want to keep the driveability. Im not saying my stuff is not reliable but im looking for something diffrent now. specially now that i own a house it's harder to get things together specially if i beat on it more . Im looking to build something in the 9 to 1 range with a mild cam edelbrock performer intake . This is just a thought my current 355 took me a year to build it has been over a year since i started and im hoping to get it in sometime this month and maybe hit the track early june. This build will take sometime and lots of planning and im approaching it in a much diffrent manner. To put it in perspective Unlike before when i had money to blow so to speak and i didnt care how long stuff lasted now i got bills and stuff which do not allow me to blow money on short lived experiments. As long as the new 355 stays together for a a few years trouble free im happy and it gives me time to build a well sorted out sb. I still did not get to do somethings with the 355 that i would have liked but the important stuff was done .

coppercutlass

Doublev those heads are not going anywhere they are currently on my 355 i just built and am yet to run. I have too much money in them to sell them so im stuck with them for a while.

captjim

Another option, and a better one IMO if you want to lose a point of compression is to swap the shaved #6s and use #8s. Cr with flat tops is around 9 to 1. Use a 210 can on a 112, run 14.0s, squirt it and go high 11s.

coppercutlass

The probes have i think a 3cc valve relifes cut into them not sure on the cc's but thats what i have. I ran high 13's on a 9 to 1 combo but that was with cast pistons i want to essentially do that same build but with forged pistons It had a very mild cam it was the comp 260h . I"ll have to see if i can find a set of 8 heads. Im probably gonna run stock rockers I really want to keep this thing sweet and simple. Im thinking of using the edelbrock performer nitrous set up.

captjim

I used that kit with a 53/57 tune and knocked off 1.2 in the 1/4. Realistically, once you get past mid 12s you need to upgrade rear ends, suspensions, etc. I think a high 13 second reliable car that runs low 12s on nitrous is all you really need.

coppercutlass

That's what I want. It's gonna take sometime but. It's gonna get done right. With complete durability in mind.

DeltaPace77

I wouldn't do BB heads on a SB, as just going cause fitment issues. First of all, ports aren't going to match up, among other things.

coppercutlass

I worked out a deal with another forum member. I got a set of 8's.