At the present time I'm running a set of factory '041 heads. These are 64cc chambers with 1.94/1.50 valves, some porting and an intake vol of about 160cc.
I'm considering upgrading to a set of alum heads, and I'm aware that there are advantages and disadvantages to increasing the intake runner vol. So I'm hoping that maybe some of the guys who've upgraded from a set of factory heads similar to the ones I've been using, to some 195cc aftermarket alum heads could give some info on how they compare.
I'd like to gain as much top end as I can, but I'm concerned about losing too much bottom end TQ. So specifically what I'd like to find out is, how much bottom end is actually sacrificed when factory heads are swapped out for a set of aftermarket 195s.
I'm using a Crane 272 cam (216*@.050) and as it is right now the drivability around town is pretty good, I can lug it at 1500rpm if I want to and there's still some responsiveness to it, which I like.
But if I could get a set of heads with more intake vol for some better top end potential without throwing away the bottom end TQ, that would be really great.
I'm sure that some 180cc heads would work well, but how about the 195s. Any ideas on that?

Thanks

 

To see the benefit of the new heads you'd want to get rid of that cam and get one with high(er) lift.
Aftermarket heads really pull away from a factory head at high lift. .500"+++ Set it up right and the little bit of low end torque you think you're going to loose will be nothing compared to the big power gain at 3500rpm+

Make the whole motor breath. then re- gear the car to take advantage of the increased rpm range and upper end power. Forget about lugging it at 1500, doesn't get you any thing.
What rear gear ratio do you have now? what intake manifold are you using?

 

Thanks F-Bird

At the present time the engine I have isn't being used in an F body. But when My '85 IROC is ready, I'll take this engine and transplant it in there.
My '85 has 3.43 gears, and and I'm trying to make a decision between an LT1 retrofit, or an LT4, or a Miniram.
I don't know where to get any deals on used LT4 equipment, so if I were going to go with 195cc heads it's very possible I'd go with the Miniram.
In my original question, it might have sounded like I want to go around lugging my engine all the time. But that's not the case at all. The thing I don't want however, is to have an engine that gets horrible fuel economy in town because I can't shift out of second... If you know what I mean.
A new cam is in the picture for later on.
I'm just asking around to find out how much I can build up my engine without turning it into something that has poor street manners or I can't afford to drive.

 

The MiniRam could theoretically be used on an otherwise stock TPI motor. In fact that's what it was originally intended for when it came out, was as a direct swap-out for TPI.

Of course, that would be sort of pointless, considering that its very short runners encourage excellent high-RPM operation, which in turn requires a big cam, which in turn leads to poor street manners. But, with appropriate parts choices (like a solid roller cam) you could maximize the performance without paying too much of a penalty in street manners.

I'd put a MiniRam on a motor a long time before doing the LT1 thing.

You can pick one up on ebay once in a while, they usually go for about $650-800. You very very rarely see a MR3 on there though. Then you need the fuel rails, which will run the ebay price up to about $1000.

 

Thanks for the reply RB
As long as the subject of solid rollers has been brought up... I've recently made the commitment to buy a Comp XR274R-12 cam (112 lsa) and I'm wondering what anyone might be able to tell me about what to expect out of a 350 with that cam, and a set of 195cc aftermarket alum heads and a miniram.
How would the idle quality be? And drivability in town?
I'm already pretty sure it would pull hard to over 6000rpm.
If a 350 would be too nasty, maybe I should build a stroker.

I had a chance to look at some DD charts for that cam, and it actually showed some impressive TQ all the way from 2000rpm to 6500.
Any thoughts on that?

Thanks