Coming back with a build! Need advice!

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I agree with IQ. I didn't realize the 440 crank part. If you stuck with the 383 crank it would be more do-able. You'll definately have some probelms using the 440 crank. Static climbs above 11:1 using the .039 gasket I'd normally run.
 
moper, I think he is using the 383 crank and is right at 10.47 compression. The dynamic compression calculator that I use has him right at 8.8:1 with that cam and I believe that could cause him problems.
 
IQ52 said:
moper, I think he is using the 383 crank and is right at 10.47 compression. The dynamic compression calculator that I use has him right at 8.8:1 with that cam and I believe that could cause him problems.
Click to expand...
Yes, not enough time to do a stroker, just want to drive it so I'm rebuilding the stock 71 383.

Again how will the higher compression hurt using the dome pistons?

build specs planned-
Block 0 decked
Stock crank w/ ARP main bolts
Stock rods w/ ARP bolts
KB400-.030" pistons (-5cc dome(not dish) - .030" over bore)
Balanced rotating assembly
Comp 280/280 .480"/.480" 110*LSA hyd cam will be degreed (same cam that was broke in in the original build in October)
Stock pushrods/rockers
Ported 440source Stealth heads - will have 8 new intake valves, new spring kit as well, MP .040" head gaskets (Felpro's)
Gasket matched Performer RPM intake w/ 1" open spacer
3310 750vs Holley carb it had
Same TTi 2"i/3.5"o headers/3" X pipe Dynomax Ultraflow exhaust
Same sfi flex plate/Hughes 3500 stall
 
Oh - gotcha. I thought i was following closely enough. Guess not..lol.
I still agree with IQ - I think it could be doable but it's a lot to ask and your tune better be spot on. I'd rather see a dynamic .5 point lower. I'd go with the flat tops.
 
IQ - going off that article the build is theoretically just a tad to high on dynamic compression.. I already use pump non oxy 91, my cooling system is proven to keep the motor cool at 160*-180*.. (3 -1" core aluminum rad, aluminum heads/Milodon WP/WP housing - 2 10" electric fans set to turn on at 160* at the upper rad hose)

I know how to tune a carb, and well I cheated there - I have a wideband mounted in the car..

I'll be honest I'm worried about PTV with the dome pistons as they already hit once.. all 8 intake valves hit the stock flat tops, with a MP .020" shim head gaskets, 80cc chamber..

Here is some other combinations I came up with-

flat tops (5cc reliefs)
0 deck
.020" HG
80cc chamber
9.86:1 static

^ same but with .040" HG
9.42:1 static

no 0 deck - piston .040" in bore
flat tops 5cc relief
.040" HG
80cc chamber
8.86:1 static

^ same but .020" HG
9.02:1 static

no 0 deck - piston .040" in bore
dome pistons 5cc dome
.020" HG
9.92:1 static

^ same but .040" HG
9.47:1 static

0 deck
dome pistons 5cc dome
.040" HG
10.42:1

^ same but .020" HG
10.98:1 static

So maybe I should go with the first combo and a .040" HG for a 9.42:1 static and bring the dynamic down a bit?
 
I'm reading the thread and see some very smart guys talking about the risk of detonation because of the compression ratio and small cam. I also see the term "dynamic compression ratio" a lot in the big block forum. I don't know a lot about dynamic compression ratio but I assume its a calculation that takes a bunch of factors and arrives at a number. With that said I want to share my opinion for what its worth. I have always preferred to push the limits on compression and not in search of higher gross output. Its been my experience the keeping the CR as high as one can get away with makes a car more fun to drive. My 440 has flat top pistons at zero deck, Felpro 1009 gaskets with .038 compressed thickness and Stealth heads that have been milled .050 which brings the chambers down to about 75cc. My cam has 254/260 duration@ .050 lift. I have no idea what that brings the dynamic compression ratio to but I do know the static CR is somewhere between 11.25 and 11.5 to 1. The cranking pressure is 210 psi. I originally ran it on pump 93 with 10% ethanol. It ran good but I heard a slight rattle at tip in a few times and it dieseled a couple of times when I shut it off so I knew I needed more octane. I solved the problem by using Klotz KL 628 octane booster. It is a premium product like Torco or some of the other brands and I buy it of Amazon for $55 a gallon. I mix it one ounce to a gallon so it only adds 43 cents to the cost of a gallon of fuel and I've been running it for two years with no detonation or problems at all. What I'm getting at is I definitely do not regret going with the higher compression compared to any low compression performance engines I've had or built. Also the premium octane boosters like Klotz or Torco can be mixed at higher concentrations for even higher octane if needed. The main reasons I like high CR are 1) better, more crisp throttle response. 2) much better off idle part throttle torque and 3)a better sounding and running engine, and 4) the engine starts easier provided the starter and available volts and current can sufficiently crank it. Cylinder pressure does that.
 
Well parts are ordered! KB400's, ARP rod bolts, and Clevite P series bearings (.010" under)

Going to return the ARP main bolts, and Mahle rings I got and buy the gaskets needed to put it together.. Jake at SRE has already line honed, and ordered piston rings, and a valve train kit for the heads.. probably buy the Performer RPM as well!
 
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