FOUND info i needed

My neigbors kid needs a motor replaced. I have a cheap shortblock, cast cast, etc, was a Thunderbolt motor, crank snapped, all else checked out.

I have some 193 swirl ports that were on it running good, no leaks, nothing.

Can these heads support a .480 lift cam? I read one thing about them, then others,some yahoo says he got 220cfm porting, i doubt, but anything is possible.

Its in a 71 Nova, so would hate to put just a stock motor in, but aint giving up camel humps for a favor.

Also do they need a special intake? I could have sworn the motor i took apart had a rpm on it. I have an extra rpm here and thats the only place it could have come from.

ANyting to do to them to support a 1500-5800 powerband? I know they were considered a failure, but also heard good for torque and trucks.

.480 lift- probably not. The swirlies I took off my old 92 Camaro 305 TBI motor I checked and the retainers actually had only .450" clearance to the top of the seal- even less than many other stock heads. Understandable considering the factory cam they used in those TBI motors had LESS THAN .400" valve lift!

Swirl ports all used the 87-up intake bolt pattern to my knowlege (2 center bolts "stood up" at a steeper angle than 86-down heads). So yes, you can put a Performer RPM on it IF you modify those 2 center bolt holes on both sides. Intake and water ports are in the same place as earlier heads, though.

I used a set of pre-86 smogger heads on one temp motor that I used while waiting to finish my real motor. Found the same exact thing - retainer to seal clearance of .450" to 460" with umbrella seals.

i checked that yesterday after posting when I read about what stock cams where and the largest replacement cams people were using.

I have a good set of 487's to give him, they are around 72cc now so its 9:2-1 motor now and not embarrasing altogether.

Some guy on a third gen board is claiming he ported them to 231cfm at .500 lift. Mostly the whole thread was about slamming them into the ground. That step is a interesting idea, I guess ironed out in the LT1 design, but the step drops right down into a brick wall turn is how it looks, even if speed could pick up in there, it gets smacked in the face.

I have some real heads for sale in the swap section (world products sportsman IIs, low miles, 64cc heads for 10:1 squeeze). The 113s would not be worth wasting a 480 lift cam on unless you ported them like that guy did, but that is a lot of time to spend on those heads.