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Discussion Starter · #1 ·
I have a big block duster that needs more power (okay, it doesn't really need more power; it is pretty quick, but I have an untreatable case of the screw-with-its). I have been fine tuning it to make it as driveable as possible and right now it is very pleasant to drive with good idle vacuum and throttle response. I would like to continue to make improvements to power and acceleration without affecting the driveability of the car, since I actually drive it around and take it on shorter trips.

My present combo:

-'77 400 big block, bored .030" over
-keith black hypereutectic pistons with an actual 9:1 compression ratio
-stock 452 iron heads
-Summit hydraulic cam 282/292 advertised, 224/234 @ .050, .465/.488" lift on a 114 LSA
-Mopar windage tray
-Edelbrock performer rpm intake manifold
-Holley 750 cfm carb with vacuum secondaries
-cheapo 11" edelbrock air cleaner
-stock exhaust manifolds
-dual 2 1/2" pipes with 18" glasspack mufflers
-stock torque converter
-3.23:1 gears

What I am considering:

-Schumacher headers
-Summit 3" header-back exhaust
-flowmaster or Vforce mufflers
- ~2500 stall torque converter
-sealed cold air induction with K&N X-stream air cleaner
-port the stock 452 heads and add larger valves

So how does this plan sound? I want to stick with the cam that I have and I don't want to get into the short block; more or less just optimize the combo that I have by improving breathing. I also don't want to upgrade to an HP style carb because I don't want to lose the choke; it is nice for quick starts in cooler weather. Any thoughts? How big can I go with the valves before shrouding becomes an issue? I am thinking maybe 2.14" intake and 1.88" exhaust like some of the popular aftermarket heads use. Thanks!
 

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Discussion Starter · #3 ·
The exhaust manifolds I have now are not the high performance manifolds; they are log-style manifolds from a '60s B-body according to the casting numbers. The big block headers from schumacher supposedly don't require any cutting, but they do have smaller primaries; I believe 1 3/4". They are expensive, though; they start at around $600 I think.

The reason I would consider porting these heads vs going aftermarket is that I would be attempting the porting myself. I posted a topic back in the spring about porting these heads and a set of 318 swirl port heads; I finally started working on the 318 heads, and that seems to be going okay. I don't think I have ruined the heads yet :p. It is taking a long time to do the work, since I have somewhat limited spare time right this minute. I will get have the 318 heads inspected at the local machine shop when I get done to make sure they are passable and that I didn't ruin anything, and if all goes well I would like to attempt porting on my big block heads.

Do you know what it typically costs to have new valve seats cut?
 
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