Tuning my engine??

[Guest mattrp]

I have a 305 and T5 which I dropped into my zcar two months ago. I slapped a holley 600 single pumper that I had laying around on the engine. This carb was rebuilt and tuned beatifully after many hours of work for a stock 350. My 305 has a medium cam in it, but is otherwise stock. Here is my issue:

 

The car appears to have more power when the engine is slightly cold, like 170, before it has warmed up fully. It pulls real hard there, and is smooth. Once it gets to 205 where it sits, the power decreases and the engine starts to run a little rough throughout the rpm band.

 

I admit I have not done a full out tune on the carb, but have fiddled a little. In chasing this inconsistency I have changed cap, rotor, wires, added accel supercoil, readjusted valve lash, replaced a failed and vibrating fan clutch with a flex fan.

 

I don't know anything about jetting a carb, do you think this smaller engine needs a little less gas to make it smooth.

 

It also seems to dump a cloud of smoke every time I decelerate and downshift rapidly, but at no other time. Any ideas???

 

Other than that, I will never regret this V8 conversion, best idea ever.

 

Matt

72 500z

[Mikelly]

Yup, the carb is getting way too much fuel. I'd find out the jetts that are in it and back off two to three sizes on each.

 

Also, you might want to put a cooler thermostat in that thing and try to get it running cooler overall. More power to be had in a Chevy running under 190 degrees.

 

Mike

 

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"I will not be a spectator in the sport of life!"

mjk

[Guest mattrp]

Cooler hugh, That sounds like a good idea. If there is more power down there, why not go down there. I will try that.

 

Thanks

Matt

72 500z