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Another 383 build with a couple questions. Let me know what you think.

Mark Barnes

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Apologies for the long post, but...
I have been reading intently any threads containing info about stock stroke 383 builds, especially ones like this (383 build?) that contain info pretty close to where I'm currently at.
'66 383 block cleaned, sonic tested, bored .030, mains align honed, deck cut to zero with SpeedPro 2315's and stock rods.
Stock forged crank cut .010/.010.
Crower 294FDP SFT cam installed @ 108* C/L. I 240*, E 244* @ .050. Lift w/1.5 rockers- I .519, E .529
Comp 2901 oil thru solid lifters
Manton 3/8" oil thru pushrods
ARP rod, main and head bolts

1-7/8 Trick Flow headers

Holley 80531 850 cfm carb, vacuum secondaries
Edelbrock Performer RPM intake

HEADS
Home ported 516 castings with 2.14, 1.81 stainless valves. Measured 76CC chambers. Single .005 cleanup cut on head surface.
Crower 68340 double springs with damper, Crower retainers and locks.
PRW 440 1.5 roller rockers

Trans-
Fresh BB 727 with PTC 9 1/2" 3K stall torque convertor and TF2 shift kit.
8-3/4 rear w/3.91 Suregrip, 28" drag radials under 3800lb.? Belvedere ll.

So there's my setup, should be completed/installed end of July. Going forward, I plan to replace the iron heads with TF 240's, but right now I'm getting tired of pissing away money.

My questions for the brilliant minds of FBBO-

1. When I dreamed up this mess, I was sure I would run into valve to piston clearance issues. Using a Fel Pro blue head gasket (.039 compressed), I clayed the pistons and got +/- .110 I, .125 E clearance. Did it three times because I couldn't believe it. Came out the same every time. I know there are better ways to measure, and I intend to try it later today, but I thought the clearances would be much tighter. I was all ready to take the Isky tool to it. Could it be I might actually get away without eyebrowing the pistons?
One other issue that I found was when I installed the pistons and rotated them up to deck height, they seem slightly cocked in the bore....by my measurements with a dial indicator...the side of the piston closest to the front of the motor is level with deck height. The side towards the back of the motor is .005 over deck height.
Considering I only have .039 clearance with the Felpro gasket, am I going to run into piston/head clearance problems when the motor heats up? Should I maybe go with Cometics at .050 to make sure, yet still keep the quench I was looking for?
I would appreciate any and all comments, positive, negative or otherwise, including on my combo. You can call me an asshole if you want...but you gotta get in line like everyone else. At least you'll get to meet my wife and kids there, so there's that...
 
Piston to valve would be my biggest concern. If changing heads later on it would be a good idea to check how deep the valves are above the cylinder head deck.
I don't know version or quality of the PRW rocker arms? Long time ago, I gambled on some inexpensive stainless roller rockers, and the rollers wore really quickly (may have been sliding and not rolling, and the pushrod tips were not getting good oiling, but I had no pushrod oiling pushrods, not hollow pushrods like you have?

I think my 383 issue was using the single crower spring and over-reving the motor. I should have done the dual spring in the first place.

L2315 piston.jpg
 
Your piston to head clearance is just fine. The normal rule of thumb is 0.035" for iron rids and 0.045" for aluminum rods.
 
Your valve to piston clearance sounds like I would expect from my past experience with TRW/SP piston builds with a cam of that size. The only thing I would have done different is use the Crane or Isky ductile iron rocker arms and not the oil thru lifters/pushrods and those rockers.

Sounds like a pretty good build overall, should be reliable to 6,500 RPM with a 6 quart or more oil pan.
 
Your piston to valve is fine, I've run much less on 7000 RPM motor. The piston to head is fine with the .039 head gasket. The big valve, ported 516's should work well with that cam. Did you "eyebrow" the top of the cylinder bores to help the flow?
 
If I read your post right you pistons are cocked in line with the piston pin?
If they are something is wrong.
The con rod is bent or the piston pin hole has been honed crooked or something like that.
If the motor runs and the piston is cocked over 5 thou it will wear very quickly.
Or the pressure will burn up the big end bearing in no time.
 
Measuring deck height can be calculated two ways. Rock the piston both ways and average the measurement. Or measure directly in the middle of the piston. Method two is not always possible.
Doug
 
Looks like a pretty good result... Piston to head is fine, and if your numbers are right (And since you've double check I'm sure they are) your piston to valve clearance is fine as well... Should be a stout 383... Have Fun!!
 
as Steve340 mentioned, I would double check the piston "tilt". Is it a mirage? Is it real? Are all the pistons that way or is it just one/two? It seems unlikely, but it is "possible"

Your combo looks like a good one, motor and otherwise. If you're driving aggressively and not doing too much highway driving, you will love that 3.91/stall combo
 
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