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#CHSB-3.60-HP50	50cc Small Block 3.60 High Port Cyl. Head
#CHSB-3.60-HP70	70cc Small Block 3.60 High Port Cyl. Head
#CHSB-4.30-HPC	Sm. Block 4.3 High Port Cant. Ex. Cyl. Head
#CHSB-4.30-HPS	Sm. Block 4.3 High Port Std. Ex. Cyl. Head

NOTE: THE 302-351RACE ONLYHEADS ARE FOR ENGINE APPLICATIONS THAT ARE IN NEED OF HIGH PORT VOLUME/C.F.M. THESE HEADS FLOW BETWEEN 350-445 C.F.M. (ON A CERTIFIED SUPER-FLOW 1020).

http://www.bluethunderauto.com/id70.html



70cc chambers. Ferrea 2.1/1.65 valves.

Dimensions: .BT 4V Difference
Intake
Deck to bottom of port 1.715 .50 +1.215
Deck to top of port 3.715 3.00 +.715
Width/Height 1.55 X 2.00 2.5X1.75

Exhaust
Deck to bottom of port 2.35 .90 +1.450
Deck to top of port 3.875 2.90 +.975
Width/Height 1.55X2.00 1.75X2.00

Width C/L of head bolt to outer edge
Intake side: Same as 4V
Exhaust: +.330
Port flow
"Heads were nicely tidied up as can be seen in photos. However I wouldn't classify them as being ported, but definitely more than a 10 minute tidy-up."

Lift....Int....Ex w/o pipe....ex w/pipe

.2______141_______124____________129
.3______191_______165____________172
.4______236_______194____________200
.5______273_______213____________219
.55_____288_______219____________227
.6______302_______221____________231
.65_____313_______224____________233
.7______323_______227____________236
.75_____329_______229____________239