318 bogging at high rpm, but only in first gear?
Could be a fuel issue... but probably something like tons of leak down. The motor goes flat in other words. Valve springs and poor ceiling Rings will do that.
How about showing us the plugs?
How's the carb setup, jets n rods?
Are these valve spring to this stock or mild cam singles or have a dampener spring or?
Whats the cranking compression and have yo done a leak down test?
Faster it can rev up in a lower gear the more it shows up? Does it blow smoke out the breathers?
They weren't fresh plugs, I had run them briefly before in my old 318, I just had a look at them and re-gapped, they only had a few hundred km on them and were in good shape, so I'd have to swap in a fresh set to read them.
I don't know the carb setup, the intake and carb came with the engine.
Stock heads off my 1971 block, I had the machine shop clean them up, the valves were good after cleaning the carbon off of them, and he said he tested the springs and they were all within specs, and within 5 lbs of each other. Single spring, factory.
Cranking compression was around 120psi, I don't have a leakdown tester. No smoke blowing anywhere, exhaust is clean, no evidence of oil burning or anything
Fuel delivery. Blocked fuel filter, faulty pump etc. The fuel in the carb gets used up very quickly at WOT in 1st gear; in the higher gears, the fuel gets used more slowly, has time to 'catch up'.
Is the comp ratio low? If the engine wants 25* of idle timing, then you should give it 25*. 25* is not a lot for a modified engine. See below.
Compression ratio would be fairly low, standard bore 1974 318, with stock 1971 318 heads, so likely 8:1 or so? Only real mods are the 4 bbl, and the timing set. Possibly a mild cam, I think the previous owner nuked the top-end, as it had aftermarket pushrods, 360 heads, new timing set, and old valve marks on the piston tops hidden under some carbon build-up.
1) If the distributor is factory, it was likely curved for 5* initial, and 30 degrees in the flyweights. for a total of 35Degrees..
With 18* initial now, you are trying to run 53* of Power-Timing, and the engine is complaining by detonation, which kills power.
2) With hi-compression heads on a low-compression short, you get an intermediate compression engine, that may be detonation-prone. It depends on where the Quench lands.
3) With 3.23 gears, Second gear works out to possibly 4500= 68mph, and 318s with factory springs usually float the valves about there, so perhaps you have a third problem.
Numbers 1 and 3 you can fix fairly easily.
But number 2 may require better octane gas than you can get at the pump. A high stall convertor, and/or more rear gear, and/or delayed max-ignition timing, may help. But if your Quench is in the zone of 050 to 080, it may not be fixable.
Happy HotRodding
But honestly, you gotta get the Power-Timing under control before anything..
It's not a stock distributor, it is a Proform 66991 distributor, and I am running an Accel Super Stock coil.
The heads aren't high compression, they are stock 1971 heads (2843675 casting number), with factory valves.
I haven't a clue what quench is, or how to measure it. I've only come across the term in a couple of posts here, and haven't looked into it.
I do have another fuel filter I could swap in, and a carb rebuild kit. I suppose I should go with that, and try to figure out my total timing first and see where I get? I was afraid to advance the ignition timing past 20 degrees, as I'm worried I'll get pinging at high rpms and won't hear it. The proform is easily adjustable for the advance, so if I get my hands on a timing light that can help, I'll do that. If the engine wants 20 degrees initial timing, does that change how much total timing I should be aiming for, or should I be going for that 34-36 degrees that it seems most people recommend for a 318? Is there a way to tell what the engine needs for total timing, other than backing off if there is detonation?
Thanks!