CUTLASS 357 sbc swap

[blackgbody]

I have an 1986 cutlass two door, with a 357.
185 64cc heads, 2.02 195 valves. 5 angle valve job,
Summit stage 2 intake, gasket matched.
howards cam 470 470 lift, 275 275 advertised, 108lsa, 104 centerline. Installed as described on card.
2 inch duals, 373 rear gears.
.035 quench
215 psi cranking compression.
New 650 avs 2 carb.
Vacuum around 17 at idle. Steady

There is basically no lope at idle, and sounds like a small misfire at idle (800rpm) when you listen to the exhaust, when u cruise 40km hr and floor it, it dosent come alive, almost like it cant breathe, rpm wont spin up as you would expect.

Always been like this, new rebuild with only 3 tanks of gas used. 91 octane plus octane booster. 9.77 :1 static compression. 8.6 dynamic. Tried different carbs and still the same. Timing is 36 all in, And been tried at all different kinds of setting with no improvement...

Exhaust too small? Is it all because of a torque converter? Brand new hei set up.

Thanks

 

[olds307 and 403]

What trans? What torque converter? Your carb is small, a 750 cfm would be better but should still have plenty of power. Why did you go with such small exhaust? What is your timing curve with such high cranking compression?

 

[blackgbody]

What trans? What torque converter? Your carb is small, a 750 cfm would be better but should still have plenty of power. Why did you go with such small exhaust? What is your timing curve with such high cranking compression?

It was the original th200 and stock tq converter, currently installing a th400 with 2200 to 2800 stall.
Exhaust was that size all along so did mot replace it....yet...
Timing is all in at 2800 or 2900 -- 36 degrees. And around 30degrees at 2500rpm

 

[bracketchev1221]

Is this through the factory exhaust manifolds, the cam is small, so its not going to be an animal. Also, is the carburetor getting full throttle, is it getting good fuel pressure and airflow? And finally, the stock converter isn't helping, but the lower gear in the t-200 is a benefit.

 

[SoFloG]

Exhaust and converter definiteley good place to start. What is your fuel delivery situation? Plugs?

 

[SoFloG]

Post some pics of the engine so we can put eyes on it

 

[blackgbody]

Is this through the factory exhaust manifolds, the cam is small, so its not going to be an animal. Also, is the carburetor getting full throttle, is it getting good fuel pressure and airflow? And finally, the stock converter isn't helping, but the lower gear in the t-200 is a benefit.

Through hedman headers 3 inch collectors into 2.5 then into 2inch back.
Tried 750 holley DP same thing.
3 inch edelbrock air cleaner, tried with it off...same.
Electric fans
No A.C

Exhaust and converter definiteley good place to start. What is your fuel delivery situation? Plugs?

All 8 , dark brown, look pretty near perfect color

 

[SoFloG]

Through hedman headers 3 inch collectors into 2.5 then into 2inch back.
Tried 750 holley DP same thing.
3 inch edelbrock air cleaner, tried with it off...same.
Electric fans
No A.C

All 8 , dark brown, look pretty near perfect color

Have you tried new plugs or are they the same since initial start up and break in? Have you run it with open headers?

 

[blackgbody]

Post some pics of the engine so we can put eyes on it

Post some pics of the engine so we can put eyes on it

Have you tried new plugs or are they the same since initial start up and break in? Have you run it with open headers?

Same plugs, since right AFTER the break in cam run. Havent tried open headers.
But i Can try it. 😁

Replacing the transmission with a newly built th400 with a stall now.

also got some FR5 plugs on order.