Don't know if it goes here, but I can try.

I am about to buy the 220cc Pro Action heads for a SBC. Going to have the holes and whatnot welded up for LT1 uses. My question is, are these heads still any good? I know they used to be, but I believe they have different owners now. If someone has used these, what kind of numbers are you laying down on say a 355 hyd roller?

 

They are killer heads--ask me how I know--- if ported right. My ports are 247CC's and converted with 62CC chambers.
Watch what headers ya buy because of plug clearance problems.
Comp/RHS bought the ProTopline factory and the head castings are made in the same place and with the same molds.

 

I second. They are awesome heads for a good price.

You need to watch for pushrod to intake port clearance, almost every set I use needs to be clearanced in that area.

 

My shaft rockers are both offset .180 and the push rods are damn near straight up and down( close enough ya can't see it with your eye) with no lifter offset and no port grinding on the outside.
Ya will have to check pushrod size depending on rocker ratio for hitting on the intake flange and inside corner of head. 3/8" tapered to 7/16" was as big as I could fit with a little grinding.

 

247CC's

Where does that engine redline?

 

We using the stock ecm.......we going against conventional wisdom as they say.



David

 

247cc? pocket change.. lol.. conventional sbc heads are the way to go nowaday's w/ the junk that's out there for our car.. i have a set of 245 RR's going on my 396.. No pro action, but similar and the perf. that these style heads offer are 2nd to none... Make sure you have someone who's doing the welding to the head that know's what they're doing.. Too much $$$ to waste on someone's lack of know how.. goodluck w/ the build and keep us posted...

 

I'd rather run a Dart casting with the new platinum port in them that's being phased in the Pro 1's. They are a better standard port head. The Pro Top Lines and All Pro's are better for raised runner stuff but there are a few other choices out there that are killer as well.

Bret

 

The ports being too big is an old wives tail. If ya got everything else ya need um that big.
Port volume also includes LENGTH.

 

Okay here's the $64,000 question: heads of this caliber I'm assuming flow in the 300+ range, but are they suitable to be used with the more "popular" LT1 cams? (Hotcam? LE2? Crane 227?) Or, assuming you bolted these onto a run-of-the-mill 355 LT1: would you need to run a 24X/25X duration cam and not expect torque to show up on a dyno graph anywhere under 3,000rpm to be able to make effective use out of a head like this?

 

Bigger heads= smaller cam of the right design for the same power level. I would suggest a cam designed by someone who knows the set up and purpose.
If ya get in the 325/350 range that's capable of 670/715 FWHP being supported with everything else being correct.

 

MOst folk's don't clearly understand that theory larry, can ya please break it down for us..

 

You can read books about building engines until you're blue in the face, but something that doesn't show up in engine building books is the why? behind things. As in, why wouldn't you want to rev higher?...why wouldn't you want more horesepower?...why wouldn't you want more cubic inches?...etc.

Seems that alot of authors assume that the answers to questions like this are always "yes," and tailor their speech accordingly. There must be some validity to that, because it's not often that you see somebody who goes ***** to the wall and does something like build an engine around a set of Arao 4-valve heads but then turns around and runs a Hotcam in it. I think questions like this never get asked because in doing so I believe you're in danger of being labeled a "sissy," so info of this nature tends to be scarce.

 

An engine takes XXX number of CFM's of air to put the fuel in with to make a given HP number. If ya got BIG heads then the duration(time the valve is open) does not have to be as much to make the HP. You are getting the air in that ya need with good ports.The overlap can be brought into a sane number of degrees also but ya still have to have some. The lift should be figured by your valve size and curtain area (ya got to get the valve out of the airflow path as much as possible)and should remain pretty consistent with whatever cam ya run.(cause ya don't change valve size every day)
If ya go with a BIG/NASTY cam ya are just shifting the HP/TQ curve UP in the power band.

 

What all has to be done to convert them?