Ignition Timing Locked or not??

[BigRedMachine]

Motor is a 355 10:1 compression, hydraulic cam, camel hump heads. The Distibutor had timing locked for use on a previous engine. Question is should I leave it this way for this motor or change it back??

[mytmouz]

Strip only, leave it locked. Any street use, unlock it...

[adamsvega]

if your cam has 245 or more at .050 you can leave it be . i prefer to use weight,limiters and springs to set the total advance in before leave rpm . and have enough retard at start rpm to help it start . camel hump heads and flat tops like alot of timing

[BigRedMachine]

How much is a lot??

[BigRedMachine]

Cam Specs are as follows: duration is just about where you said. Should I leave it?
Basic Operating RPM Range: 2,500-6,500
Intake Duration at 050 inch Lift: 244
Exhaust Duration at 050 inch Lift: 244
Duration at 050 inch Lift: 244 int./244 exh.
Advertised Intake Duration: 292
Advertised Exhaust Duration: 292
Advertised Duration: 292 int./292 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.501 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.501 in.
Valve Lift with Factory Rocker Arm Ratio: 0.501 int./0.501 exh. lift
Lobe Separation (degrees): 110

[adamsvega]

300/250 .500 solid on 9.8-1 355 with efficient chamber and portwork wants above 37 and worked best at 40 (my set up). have seen those heads on a combo want 42 thus the need for alittle retard at start up . only your mph will tell you whats right for your combo . as long as you limit total advance to a min. you can weight and spring it to fit your bill . in oldsmobile motors we ran hei set ups with vac.adv. and 15 deg. mech . to let the thing leave clean, idle good and not heat up on the return what a pain thank god your just trying to tune a chevy!

[BigRedMachine]

So should I leave it locked or no??? Heads do have port work and valve job done to them. I drove it on the street in traffic for a half hour and it didnt overheat at all. I have timing set at 36 right now. Thats what I set it at when I just dropped the motor in.

[BigRedMachine]

??

[adamsvega]

how do ya know what it wants with out trying??? if you mph goes up keep adding! if it gets hard to start put the mech. advance back in and curve it .if you can't curve it yourself ya can hook up vac. adv. to get the low rpm unloaded timming back up .

i dont know what your piston tops look like so i cant relate advice .just try . the camel heads are real junk relatively speaking !!!! you can get truck heads or cheap after market jobs that will smoke em .average port work yields about 220-230 cfm with out beer can thick push rod pinch! a vortec is always 30 cfm better through all but .550+ lift

[BigRedMachine]

I have a set of World Sportsman 2's with 2.055/1.6's. They have extensive port work and chamber work as well as a competition angle valve job. Had them on the flow bench and they flow about 265cfm and are good for about 6700 rpm. I would assume I should just throw those heads on instead of using the camels and I should pick up a helluva lot.

Pistons are two relief flat top forged speed pro

[adamsvega]

those are my favorite elcheapo heads .at 265 there not beer cans and velocity is through the roof with a good chamber for flat tops and small domes . i ran those size heads on the wagon to 9.80's in a 385 sbc never saw 7000 rpms . if ya got em use em!!!! unless you got a 30 deg. seat or angle milled you will need to be .540 or better lift and chamfer the block to the head gasket to unshroud the valves on a 4.0-4.06 bore .