[bones427]

i have a 340 mopar and it has eddy rpm heads with a 171cc runner. it has 2.02 valves and i have been told to install 2.08's. Also was told to stick with the 2.02 and that i wouldn't see much gain from the change. Because at his cu.in. the velocity/speed is what i need. What do you guys think? this is a street/strip engine 11.6 comp. soild roller .665/.668 258/[email protected] 108 lc 3400 lbs.

 

[Prochamro]

I ran a Procharged 355 SBC with AFR 195 with 2.02 valves and a small blower cam 0.450's lift. Changed to AFR 195 comps with 2.08 valves and 1.6 rockers and noticed a (seat of the pants) increase in power.......Maybe 5 to 10%. No loss in torque under 3000rpm at all. In fact it became almost unstreetable as I could burn out at under 2750rpm and would occasionally loose traction mid corner at slow speeds when tyres were cold......

 

[67RS502]

you'd be much better porting the heads, 2.02" vavle is not the choke point.

 

[bones427]

heads are ported by Hensley Perf.

 

[SStrokerAce]

Why do you need the big valves then? I've seen more ruined SBC heads because some dingbat put a 2.08" valve on a small stock port....

Maybe someone else needs to look at the heads for you who can do a better job.

 

[scott foxwell]

Honestly, the 2.02 is already plenty big, if not too big for peak power in the 6500rpm range. Do you know the min. area for the port?

 

[bones427]

Honestly, the 2.02 is already plenty big, if not too big for peak power in the 6500rpm range. Do you know the min. area for the port?

it's 1.96 I was just going off of recommended valve size from other post's. the guy doing my head work is going to put a 2.05 valve and sleeve the intake bump so he can open it up to geta straighter port.

 

[scott foxwell]

it's 1.96 I was just going off of recommended valve size from other post's. the guy doing my head work is going to put a 2.05 valve and sleeve the intake bump so he can open it up to geta straighter port.

IMO your port is already bigger than I'd make it unless you want your peak power in the 7500rpm range, and even then I wouldn't put any bigger than a 2.02 in it. I don't see that with the cam you're running, and I doubt the bigger intake will gain you anything except a heavier valve and more shrouding.
JMO