91GTABird

I can get a set of 3973493....71-72...400..........76cc chamber heads from a friend real cheap. Maybe $100. My spring goal is a 383 LTR set-up. He has a new set of pistons he'll sell me to for
$50. That includes rods and rings also. Not to mention the rings are on and the rods have already been pressed on. He says there about 8.5:1 cr on 64cc heads. I figured it up with these specs- 4.030 x 3.75 stroke
72cc cbr heads
4.040 gasket thickness
0.040 gasket bore
-8cc pistons (im assuming)
---------------------------------------------
9.77 Comperssion Ratio
I did this on a Virtual Engine Calculator. Would the heads work good with this setup,
383
Siamesed and potrted plenum (70% done)
Temporary Ported Base (Aftermarket base coming)
AFPR
DIY Prom
26# SLP injectors
Aftermarket igniton (MSD, Crane or Jacobs)
Flowtech or Edelbrock Headers

Already done-
Custom 3" Exhaust
EGR delete
TB Bypass
DIY CAI

c4boom

are the pistons for a 383 if they are for a 350 they are going to hit the heads

89Warbird

$100 is about all they are worth to put on some truck motor not a sportscar.

91GTABird

I meant 0.040 gasket thickness and 4.040 gasket bore.

The pistons are for a 0.030 bore, thats ill i know.

Whats wrong with them warbird? If thats the case then im just gonna port my LB9 heads and use them untill i can get a something else.

So you have to match the pistons with a 3.75 crank? Why wont they work? Journal size?

1991tealRSt-topGuy

those heads are smogger junk

thats what wrong with them

400's never came with decent heads IIRC

91GTABird

Can you explain to me why 1991TealRs? I dont know anything about them?

c4boom

the ports are too small, the chambers too big, the port shape sucks and they are prone to cracking.

1991tealRSt-topGuy

what he said

c4boom

see i know what i am talking about some times

91GTABird

Thanks for the info. Ya'll saved me @100 bucks! Do yall think that my lb9 heads will work for about 1 year until i can get something better (AFR 195's?) If i use them im gonna do the hack job myself. Would a valve job be worth the money or save that until i get something better?

Off the subject but what are steam holes (493 cast)? And whats the difference in a short block and a long block?

c4boom

get your self a set of l98 heads they can be had for cheap stay away from any thing off a 305 the shamber size will make a 383 just about need race fuel and most of them had tiny valves

cgb

Short block = This normally refers to an engine without accessories, and w/o cylinder heads, intake etc. For example, block, crank, rods, pistons.

Long block = Above + cylinder heads, and sometimes intake. Usually with the harmonic balancer as well.

Steam holes are just the holes drilled in the heads and block from the factory JUST On the 400 small block. This was done because the siamesed bore of the 400 does not allow room between cylinder for coolant to flow, as in other small blocks. For any heads to work correctly with a 400, these need to be added.

Any factory 400 heads won't be that good of a choice for a performance engine.

$100 will buy you a workable set of iron L98 heads ( when ported and cleaned up, these things will flow respectable numbers for a street driven build up )

Shop around the local machine shops, race tracks, classified to find a deal on some good heads.

383, and 400's especially REALLY shine when given the heads to complement a good cam / intake choice.

Roostmeyer

iTrader: (3)

The deck hieght on a SBC is 9.025 inches stock. Stock 350 pistons have something around a 1.55" piston height (I think). Do the math 3.48/2(crank stroke) +5.7(rod length)+1.55 (piston height)=8.99". If you use a 3.75 stroke you'll have 3.75/2+5.7+1.55=9.13" so the pistons will stick out above the deck about .115".

Get some more information on the pistons/rods and we'll let you know if they're worth running or not.