79corvette

I was curious if you guys could provide some feedback on an engine build I am contemplating. I recently moved to Colorado and my engine is missing all of the emissions equipment which is a requirement out here. Since I have to get all new top end components I figured I'd rebuild the lower half as well. I was thinking of stroking it to a 383 using the components listed below. I haven't decided on heads yet but if I go with a 70cc head I calculated that the CR should be 9.75. What style camshaft would you all recommend to pass the emissions testing requirement? It sounded like valve overlap and timing would effect its abilities to pass emissions but I wasn't sure what the correlation would be. The part of Colorado I am in requires a two speed idle test with a limit of 1.5 for CO and 400 for HC. Do you think it is possible to get this setup to pass emissions?

Crankshaft:SCAT Series 9000 9-350-3750-5700
Rods:Scat Pro Comp I-Beam 2-ICR5700-7/16
Pistons: KB143-030

I don't plan to race this I just want a street car that has some good torque when I need it so I figured the 2 bolt block I have and the cast crank should be sufficient. Thanks for the help.

Taijutsu

Years ago I had my engine rebuilt and it had to be smog tested. I needed the visual parts to have an EO number to pass inspection. They turned down the timing till it ran like crap and it passed.

My 350 had 10: 1 comp and a 218-224 HR.
You might have stricter test requirements, I can't say?
Many problems can be solved w/less timing!

Let us know how it goes.

R

gkull

My house is at ~5000 feet. Altitude requires more C/R, timing, and pack as much air in the cylinder as possible. My 383 has 11.2 with 64 cc heads and -7 cc two valve relief flat tops and thin head gaskets. AFR 210 heads and mid .600 lift solid roller cam. @20 degrees advance at idle 14 degrees mechanical with and all in at 3200 rpm. I think that my additional "Ported" advance is 10 degrees. My motor is probably one of the most streetable high HP 383's on the forum


You need to talk to the local hot rod crowd about emissions.

Nevada passing the sniffer doesn't do you any good if it fails the visual checks. Like air pump, C-convertors, EGR, ........ Age of the car comes into play. Over 25 years old here can get you classic plates and after a single exam exempts you from future smog testing. Or they have a $200 rule that you get a waiver if you attempt to cause it to smog.