Visit The Dirt Forum for More Information

Author Topic:   increased exhaust valve
Mikey14
Member
posted September 20, 2004 08:50 PM
so what would happen if I had the exhaust valves increased but left the 1.94's in on a set of heads?

9.3 compression, flat tops, 509 lift cam, 355, stock manifold, stock exhaust.

iowatoolman
Member
posted September 21, 2004 09:31 PM
real good torque


Mikey14
Member
posted September 22, 2004 12:28 PM
Thanks, I thought it might breath better too. So would it move the torque up the rpm scale then? or is this a low end effect?


iowatoolman
Member
posted September 22, 2004 12:42 PM
if i remember right it is low to mid increase you can also do the same thing by changing to 1.6 rockers instead of 1.5's
that change moves the torque band peak up by about 500 rpm


Ego Racing
Member
posted September 22, 2004 12:50 PM
Helps all over the board with increased cylinder scavanging.


Xtreme12x
Member
posted September 28, 2004 07:59 PM
you gain twice what you would gain by increasing intake valve... its a common practice on hobby stock motors, then when the intake side is wore out enough you can enlarge the seat to 2.02 but until then keep it stock size... my motor has 441's with 1.94/1.6 and it is a torque monster from 6500-7200


Xtreme12x
Member
posted September 28, 2004 08:00 PM
also run a 1.6 rocker on the intake to help trick the motor...
a stock sbc head gets enough air... it has trouble getting it out