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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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Do you have the performance exhaust manifolds on her now? I am not a big fan of headers especially with the cutting necessary to get them into the A body, but for the street and non-racing, dual 2.5 or if you want, 3 inch exhaust alone will save a little money if nothing else, 3 inches gets a little bit loud,Save a little money as far as not getting headers, that is. I can set off car alarms in parking lots all day long with 3inch in the Charger. What about Edelbrock or 440 Source aluminum heads? After you get the work to port and install the larger valves, this would be about the same cost except for rocker arms (roller of course). 2500 stall is good, otherwise the 11 inch converter is 2200 stall and is factory, usually a little cheaper than aftermarket.
 

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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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You may check TTi for headers, they are about the same price I think and I know they are good. The performance manifolds are pretty good for the street and you wouldn't have to cut for the headers. As far as the seats go, that you will have to ask the machinist, prices vary quite a bit.
 

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I have had very good success machining these heads into a closed chamber design. Although this increases the compression ratio the engine becomes more detonation resistant due to the tighter squish. This is with flat top pistons though, some K.B's are a step head design in an attempt to accomplish the same thing. Although most prefer roller rockers the originals are so light they will out rev the rollers.

Thanks
Randy
 

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I like the rollers because they are adjustable and highly recommended for aluminum heads due to their geometry. If shaving the heads this much on a big block, the intake also has to be shaved to fit properly. One advantage is the floating intake with the valley pan, the downside is, the valley pan has to be trimmed to fit, otherwise the .050 you take off the heads restrict the ports, so caution in reassembly is paramount.
 

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sounds like my own ansver:
-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

the only thing i would like is a bit more comp up in the 10 range due to the
"relatively" long cam.
I could consider a cam change to a similar value cam from hughes if the summit cam
is using " chevy" lobes that doesent take the wider chrysler lifter into account with the
possibility for more radical ramps on the lobes.
 
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