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**crossy** · 06-27-2003, 04:01 PM

greg, the 840 heads are 68 era heads and are large rect port. with closed chambers .Especially on a 'smaller' motor like yours they are too much for weight it will be pushing. these heads don't come into their own until about 4500 RPM -up . They also have small combustion chambers and big blocks are fussy about high compression and todays Junk--- er-- I mean pump gas. the large oval prt heads are best suited to a performance street engine. I made 460 horse with a 396 +.030 and bone stock oval ports with closed chamber. with a .560 lift cam. and that was 20 years ago technology.

OH BTW . I would also be interested in them :-). DAVE

06-27-2003, 04:01 PM	#3
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,042	greg, the 840 heads are 68 era heads and are large rect port. with closed chambers .Especially on a 'smaller' motor like yours they are too much for weight it will be pushing. these heads don't come into their own until about 4500 RPM -up . They also have small combustion chambers and big blocks are fussy about high compression and todays Junk--- er-- I mean pump gas. the large oval prt heads are best suited to a performance street engine. I made 460 horse with a 396 +.030 and bone stock oval ports with closed chamber. with a .560 lift cam. and that was 20 years ago technology. OH BTW . I would also be interested in them :-). DAVE __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww 84,C10 SWB-Yella,stock 86 K10 SWB-Red, hopped up 305,4/S LOTS of Cummins trucks.