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Old 01-07-2012, 05:58 PM
b00tz b00tz is offline
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427 BBC tuning help

hey guys, im working on getting my 427 all tuned in and im having a little trouble so far , its kind of hard starting in the cold, and i cant manage to get it working quite right , seems to be sluggish in 3rd and 4th gears... and i know it shouldnt be because it has more than enough torque to roll it.

i know on the dyno we dropped the main jets from a 74 to a 71 and secondary from an 80 to a 78, dont know if this is the cause of my problems or not as i havent got the new jets yet.

this is all my info

427 BBC TD

punched .60 thou and balanced (439)

large oval GM heads with port work and manley 2.19 intake valves ,ferrea inconel 1.80 exhaust valves

SRP +29CC dome pistons with mahle perfect circle rings

im running comp hydraulic roller cam 11-443-8 ,
540 intake lift
560 exhuast lift
duration @ .50 is 242 int and 248 ex

scorpion 1.7 roller rockers

Dart high rise single plane intake

proform 750 double pumper with mechanical secondaries.

it made 530 horse @ 5650
550 torque @ 4400

the builder says compression should be around 10.5 : 1 , i dont have the head numbers ATM but its the standard TD truck heads.

im running 11 degrees base timing with no vacuum advance and 36 degrees total by i think 4000? i dont have a timing light ATM sorry

so far the only thing ive been able to set up properly on the carb is the idle circuit, had 10 vacuum with the idle circuit screws a half turn out, that was the best vaccum i could get.

i havent touched power valve , timing , or jets , and dont know whether or not to run vacuum advance.. im kinda lost lol never had a good engine like this before just old stock 350's... any help is appreciated.

oh btw its in my 87 chevy one ton 4wd , muncie sm465 with an np208 and 4.56 gears with 44 boggers, running a centerforce dual friction clutch.

Last edited by b00tz; 01-07-2012 at 06:07 PM.
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