I dont know squat about chev motors. What deg of timing should this motor be set at between ? And what would i need to set the gap at with a new set of plugs ? Thankx

SBChev 400 HP - block # 3951511 - 1970-73
.40 flat tops / roller rockers / edelbrock performer rpm heads / comp cams thumper cam / eldebrock performer rpm high rise intake / Holly 600 carb #80457-7 .
Ignition:
Mallory coil # 29440 / msd street fighter cdi multispark ignition # 5520 / Msd distributor #8361

 

About 36° BTDC at 3600 RPM w vac advance line disconnected. Start there, then experiment.

Yes. Some is better than none. Anything .035" - .045" should be fine.

 

Thankx
I need to re seal the intake pull distributor and re install, how do i find top dead center : Rotor pointer towards #1 cylinder remove #1 plug manually crank motor with finger in hole, and is it at tdc when it sucks yer finger or blows it out ? That sounds dirty, LoL ! No pun intended.

 

The point you're looking for, is the end of "squeeze" and the beginning of "bang". It is when the piston reaches the top of its travel after compressing the cyl contents.

 

The of the top of the compression stroke or the exhaust??. Sofa ya could explain it better.....

 

Suck
Squeeze
Bang
Blow

equals

Intake
Compression
Power
Exhaust

 

Test.Test.One-two.Is this thing on??. Test.How does explain how to time this guy's engine??.

Don't have time right now.Running out the door.Could someone properly help this guys out???.

 

I find approx tdc with finger in hole and have some bump starter over. If you can thread a bolt into crank you can turn it by wrench that way. I can also turn my motor over by socket on crank pulley bolt, but be careful with that, could very easily overtighten and break a cheap bolt.
Its best to turn slow by hand rather than starter.

Once you feel pressure on finger go slow and move piston up some more. With a small mirror and flashlight you can actually look inside bore and see piston at top. You just have to get it close enough and adjust dizzy to get it fired. As long as fuel ratio is close, it will fire with timing in the ball park, + - 20 deg

 

And when that's all sorted out go get a 750 and enjoy the 20+ HP your giving up with a 600 on that combo.

 

Whats the exact compression on this thing? Flat tops on a 400 usually is high comp 11-11.5 to 1 with a 64 cc head. What cc heads? What piston to head deck height with gasket?

If its pretty high and cam isnt closing intake valve close to 70 deg abdc at .006", the dynamic compression will be high and pump gas will be detonation prone. I may suggest start off lower on timing. 30 deg and work up from there.

 

Orr-thanks for that.

What I do in a build is leave #1 valve cover loose during the build.Once in the car,I pull that valve cover and watch the exhaust rocker go up and down,watch the intake rocker go up and down.Once both are on the null side of the cam,bring it up to -0-. That's TDC.We set the oil pump slot in the test stands at the engine plant so the slot was straight front to back.Set the dizzy so it was on #1 and drop it in.

 

Yup i have done the valve cover thing but my recent turbo build layout prevents easy access to the cover.

However i have noticed on my balancer which is a romac with 360 deg marks and stock L98 timing cover, 0 deg does line up with pointer and cylinder is at tdc, just need to be sure its compression stroke

 

Ok got it thankx for the info

 

Yep, got an Edelbrock 1413 800cfm carb to put on this weekend

 

Dont know what the compression is yet. The heads are eldebrock performer rpm 60619 / 70cc / 9/16" deck thickness.

 

Ummm ok .

 

I dunno if anyone would be interested but those valve covers that you see in my above pix i may sell. Dunno yet what i should ask for em. They are aluminum and both say pontiac trans am . Not gonna sell em on FeeBay though.

Whopsy, here a linky to pix:

http://imgur.com/a/SRQyL

 

Would changing the position of the cap to the distributor effect timing ? The msd cap has those L hook clamp/bolts that just tuck under to attach the cap, it doesn't tighten down the cap good enough to where it was little loose, so per msd instruction i cut those off and just used the recommended screws to bolt it down to distributer nice and tight. But now car will not start, getting gas and spark. The position of the cap before the mod was about an inch to the right from where is bolted down with the L shape bolts.

*** I have to change the location of the plug wires now.Refresh me memory, Does the #1 plug wire go where the rotor pointer is ?