Well we got my friend's 427 back together and running after a couple rocker arms cam apart. Everything seems to be running pretty good (valve t rain is perfect) except we cannot seem to get the timing sorted out. I'm wondering if the timing mark on the tab and/or balancer is wrong so we're going to get a piston stop and check for sure.

This engine has closed chamber heads (heavily ported into rovals) and light deshroud work in the chambers. It has TRW dome pistons and is 12.5:1 compression. Cam is a Crower solid roller on a 106 LSA with a 4,000 - 7,000+ power band (don't have exact specs but its fairly big - idles at 1,100 in gear with 6" vacuum).

What timing (total) should we start at? We tried starting at 36* and the car just didn't want to idle at all. We went to 40* and it idled a little better but it revs sluggish. After I left the owner advanced the timing more (he doesn't know exactly how much) and the car runs much better - except it starts to break up at 6,000 RPM (should pull well past 7,000). We pulled the plugs and there was no sign of detonation, just lead buildup from race fuel.

Any ideas?

PS. he's running a 4.56 gear, an old 1050 dominator carb on a 4150 intake with adapter. TH400 trans with 4500 stall.

What fuel are you running and how much quench area? If you are running race gas and the quench is less than .040 you should start at 44deg and work from there. Personally I would loose the 1050 and find a smaller carb. You really don't need it and they can be rather troublesome to get right with an auto.

Sounds like the engine wants more initial and less total. The last distributor I had on my truck did the same thing...I could bump the initial way up and the throttle response was just awesome, but it killed the top end power even though there was no signs of detonation. This may even be one of those situations where the engine will run better with a locked out advance curve. Just a thought.

He's running Torco 110 for fuel. We might throw my old Proform body O-3310 on it just to test . . .

44* :eek: I knew Big Blocks liked a little more lead esp with domed pistons, but didn't know they'd like that much more. What would you consider max safe total advance Oger? 50 ish?

I'll try to post quench height, exact cam and piston specs . . .

You might be right on the curve Travis - we really need to spend more time figuring out exactly what he got for timing marks and what kind of curve he has. Its an MSD distributor - should be easy to lock out - I think all you need to do is install a plug or pin of some type.

Hey Eric,

My 427 likes a lot of timing also, I don't know why that is but it does. I locked out the distributor so it only has maybe 10 deg of advance in it and just tuned it from there. I checked top dead center with a piston stop and found my timing marks to be off a little but it still runs best with 50 degs in it. As far as the 1050 dominator I have been running a 750 dominator and switched to a friends 1050 and the car picked up a tenth with the 1050. My motor is a mild 427 on pump gas and it still wants the timing.
Good Luck
Bill T

Most closed chamber motors like at least 48deg. I had one that ran best at 54deg. Maybe you guys are better than me but the only time I ever had a 1050 go faster than an 850 was in a dragster with a 6000 convertor.

Thanks guys. We advanced the timing to 44* (the marks are correct as it turns out) and changed the plugs and it runs now. The plugs had a fair amount of lead deposit which probably didn't help matters upstairs.