Welcome to CHR!

I’m always encouraged by young people who are learning to wrench and have the mindset to work through things and figure out problems. Sounds like you’re doing a lot of things right and we’ll certainly try to help you figure this out.

There’s only a limited number of things that could cause your issues – bear in mind that it could be a couple of these things. I would recommend the following:
1. Check your fuel pressure – I’ve seen 14PSI from a new mechanical pump and you want 4-5PSI.

2. Check compression – need to know what’s happening inside the cylinders. Do this with all 8 plugs out and with a real good strong battery (or a booster cart). Make sure you get a minimum of three complete revolutions per cylinder and preferably five or six - stay constant with all cylinders. Compression should be 100PSI (minimum) with no more than a 10% variation between lowest and highest. If you have a low cylinder, squirt a couple shots of oil down the hole and retest. If compression jumps, think bad rings. If not, think valves. (I think your ½ turn from zero lash is probably okay. I like 1/4 to 1/2 turn for stock or mild build applications.)

3. Buy (or borrow) a timing light and set initial at 8 degrees (with vacuum plugged).

4. Set idle screws at 1-1/2 turns out (may need adjustment later for fine tuning – but this will work for the initial setup).

5. When running, spray WD-40 around the intake where it meets the heads and at the base of the carb. You will know instantly if you have a vacuum leak.

And now a few questions:
1. What heads – EXACTLY - do you have?

2. If this engine was truly stock, what was it originally from? Get the numbers from front pad (on the block where the head meets) on the passenger side. This may help in determining the stock compression ratio as well as the general cam profile.

3. What head gaskets did you use?

4. Did you use new head bolts?

a. How did you tighten them?
b. What was your final torque value?
c. Did you chase the holes for the head bolts with a blind tap and clean out the hole?
d. Did you lubricate the threads?
e. Did you use sealant on any of the head bolts?

5. What do the spark plugs look like? They should be a nice light brown – not black and not bright white.

Let us know – we’re always wanting to help.

Again, welcome to CHR!
Glenn