well i got my 400 put together:

scat 400 crank, 5.7 scat rods, h616 speed pro pistons, 4vr, 401luna6 installed as-is with the crank gear of the timing chain set to zero advance/retard.

i was checking clearances using the #1 cylinder. the rods cleared the cam fine, but the intake valve hits the piston upon opening just before top dead center.

what should i try next? are new pistons in order, or? how about retarding the cam?

i'm open to any suggestions...

btw,
.518"/.530" lift
276/284 duration
243/251 .050" duration

Flycut the pistons.

Double check the TC setup for dot to dot.
Otherwise the flycut or different pistons is the only safe way to do it.
Bad news I know. Hopefully you checked all this prior to balancing. But by your assembled comment, I'm thinking not....

You simply need to have a machine shop flycut the piston valve notch some more to clear the valve. Pretty basic job for a machine shop, you need to figure out how much interference you have.

I assume you have either a small-base-circle cam or the rods supposedly clear the cam. If the rods are normal 350-style rods and not clearanced, or the cam is a regular base-circle size, you may have a rod bolt hitting a lobe, instead of a valve hitting the piston.
Tell us which you have before you start cutting on anything.....

UDHarold

What UDH said, if your running bolts and not cap screws, then you more than likely are hitting a rod. I'm running cap screws and still hit one lobe with your icl setup. Had to retard 4 deg. for a 110 icl to clear. Yeah, I know Harold...

well, with the heads off and the cam dialed in, the whole motor turns freely.

with ONLY the intake lobe set, the motor binds at about 6-7 degrees before tdc.

with ONLY the exhaust lobe set, the motor turns freely.

just for the heck of it, i changed the timing chain to "-4" and it seems to turn over just fine, the clay read about 1/4" clearance between the valve and piston! go fig...

i sure wish i could afford to cut the pistons now, but someone rear ended me in my other car and sent me into the back of a truck this morning :-\ now i have to get this nova running extremely soon, i start a new job next week (eek!)

Hey Harold, you recommended the same cam for my 406 and told me to put 1.6 rockers on the intake. I have Dart Iron Eagles with 2.05 intake, 1.6 ex and 200 cc runners. I was wondering if I should try the 1.6's on the exhaust instead.

MaTt

Originally posted by smog test reject:
well i got my 400 put together:

scat 400 crank, 5.7 scat rods, h616 speed pro pistons, 4vr, 401luna6 installed as-is with the crank gear of the timing chain set to zero advance/retard.

i was checking clearances using the #1 cylinder. the rods cleared the cam fine, but the intake valve hits the piston upon opening just before top dead center.

what should i try next? are new pistons in order, or? how about retarding the cam?

i'm open to any suggestions...

btw,
.518"/.530" lift
276/284 duration
243/251 .050" duration =
Something ain't makin sense??
The intake should not be hitting before TDC if the cam is in right as it is just starting to open.
The exhaust valve is closest just before & the intake just after TDC.

Before you do anything else you need to degree the cam & find out where it is, you may have a chain set that is screwed up or are using the wrong mark to line things up. ;)

Originally posted by Mz28att:
Hey Harold, you recommended the same cam for my 406 and told me to put 1.6 rockers on the intake. I have Dart Iron Eagles with 2.05 intake, 1.6 ex and 200 cc runners. I was wondering if I should try the 1.6's on the exhaust instead.

MaTt Not Harold, but in most cases, 1.6's on the intakes will make more power than 1.6's on both or on the exhaust only.

Thank You

MaTt