[LSG]

Mike, tell us what year your engine is. I wouldn't change the heads. If you're keeping the Performer intake and the factory irons and the 2 inch duals, fancy new aluminum heads will gain you absolutely NOTHING. Before you do anything to the engine, get a new oil pressure sending unit ( they stiffen with age, and give incorrect readings ), or better yet, get a mechanical guage and see how much pressure you actually have ! Your oil pressure might be just fine and your crusty old sender is unable to tell you ! Don't even THINK of having the crank ground untill you have had it washed and measured ! I have recently retired from the engine building shop, and can tell you from experience that at least 9 out of 10 SBF cranks only need a polish. And oil pumps don't wear out, they just don't. If you plan on keeping the 2 inch dual exhaust, don't bother changing the exhaust manifolds, its already choked off. You should look around the waterpump passages and see if the jackets are partially plugged where the pump feeds water to that side. It would be nice to know what cam you have now, before recommending others. How about testing the oil pressure with a trusted mechanical guage, and then a leakdown & compression test ? THEN we can help you figure it out. I'll be the contrary one here and recommend you keep the iron heads. They'll support 450 hp if they're done right. But you have to make other changes to use that breathing capacity, how crazy did you want to be ? LSG

 

[LSG]

Nail ! you've been holding out on me !! excellent pictures though. I'm thinking that those are 1.6 exhausts.
All, if you look at Nailbender's pics, you'll see there ISN'T tons of room to work with in there. I don't like the way many SBF heads get done with Chevy valves, you see alot of 1.84 / 1.5 combinations. The stockers was 1.78 / 1.45. The tips and overall lengths aren't right either. Yes, you can get different pushrods and springs and make it all work, but WHY make it harder on yourself than you have to ?! Aftermarket valves are available in the sizes and lengths that you need. I like to see 1.6 exhausts with a hard seat, like a SB 1625-1 from SBI. For intakes, you CAN run a 1.94, but my preference is to take the 1.94 valve and trim it down to 1.90. You can see in Nail's picture how we are getting really close to the sparkplug cut. Then, if you need to at somepoint need to give the heads a valvejob, you get new 1.94 intakes and cut them to 1.92 and run them that way. Then, finally, run them at 1.94 on the third time. Exhaust seats are replaceable, and the intakes are as well, but it is more of a pain in the arse when working so close to the plug.

Now, aftermarket aluminum heads will outflow even the BEST of the iron heads,....but I have seen lots of folks with aluminum heads, but performer intakes and cast iron exhaust and 2" twins. Thats not going to help power at all. LSG

Nail, if you should tire of those ported 289 heads, I can drive down after them,......

 

[LSG]

Rusty, we CAN beat the $1045 price per pair, and your iron heads would still have the 54 cc chamber, instead of the 62 thats in the enforcers. And you have to remember that those frequently need some touchup work. Its not like you just take them out of a box and slapp them on. Usually, at least 3 valves and seats per head have to be recut. BTDT LSG