jrsixx

First a bit of history. I have a 77 Salon with a 350, that i bought in 83 and rebuilt the engine, trans, rear end, body, suspension, etc., in 86. I got it out of storage last November...longer story. I had a folder with all the specs for everything that went into this car, it's since been "misplaced". I got it running with only a coil (had it mounted upside down), even on 23 year old gas! I built this thing when I was 21 and just starting to wrench, well, now with nearly 25 years in the business, I know a lot more, but sadly not much more when it comes to performance engine building.
I thought I was building a fast small block, #5 heads, new valves and 3 angle valve job, mild cam, new rods, pistons, assembly balanced, performer manifold, and a 600cfm Holley. Problem is, it just doesn't seem as fast as I thought it would, and now I'm thinking I did something wrong somewhere. The things that I'm thinking about are 1: cam size, 2: carb issue, 3: too high stall speed, something anything simple??
Questions are, how can I tell what cam it is short of taking it out, is there a way to check what stall speed the converter is, are there any "tricks" to adjusting Holleys?, or can anyone think of something I'm missing? Thanks for any and all help, and remember I've been a tech for 25 years, so I can and will tear into anything, but this is also the one and only performance build I've done, so I can be how shall I say "dense" about some things.

Olds64

The simplest thing to do would be to rebuild the carburetor. If it has been sitting in storage for a number of years then the gaskets are brittle and old. Rebuild the carburetor, get new gasoline in it and drive it before doing anything else.

jrsixx

I did rebuild the carb, also new plugs, wires, and of course fresh gas. It doesn't run poorly, just not what I expected I guess in the holy crap power department.

70 cutlass s

What kind of gears do you have?

jrsixx

3.73.

BIGJERR

SBO in a big car = not that fast,Sound like the gears will work ok,Maybe a some compression and a higher stall and it will get up and go! ..........or just get a 455 to slap in that badboy!

TripDeuces

Stall speed would be easy to tell. Hold the brake and give it the gas without letting the tires break free. You'll need a tach of course but whatever the engine revs to will be close to the stall speed. It's not a perfect method but you'll be close. You can also just mash the throttle and see what it revs to initially. That is actually more real world then the first method. Although your converter may be rated at 2200 stall there are too many variables to consider. The latter method will tell you all you need to know.
Without having a dial indicator on the lifter there is no way of telling what cam you have without getting a number off it. Cranking compression can tell you whether it's in the ballpark of what you need. Try to shoot for 185 psi. Once again this is variable. For example, I had a small cam with high compression and had a 230-235 cranking pressure. Very bad for detonation. However, with less compression that may have been ideal for the street. I was young and dumb once also I guess what I'm trying to say is it's not really what you have but does it all compliment each other.

jrsixx

I guess what I'm trying to say is it's not really what you have but does it all compliment each other.

That's really why I'm trying to figure out specs of the cam and stall. I've been reading a bunch about getting the combo right and I seriously doubt I hit the nail on the head 24 years ago. I mean maybe I got lucky and everything is complimentary and it's just as BIGJERR said, too little motor, too much car, but my guess is something's not quite right. I'm not looking to break any 1/4 mile records or anything, but it'd be nice to smoke the tires without having to brake torque it.
As far as cam numbers go, are they marked on the cam somewhere?

jrsixx

Wow almost 2 years later and I still don't have this figured out. To be honest, I barely touched the last year. At this point I've gotten it almost all back together, new carpet, interior and windows installed, heater core, and A/C,and a bunch of little things. I still have this nagging performance issue. One thing I came across when trying to get some more ooomph outta this ol girl, is that the base timing wants to be at 35-40 degrees to run well. Now as I've stated before, I'm no performance engine builder, but I've been wrenching almost 30 years so I've timed a few motors. This thing does NOT start like it's got 35 degrees in it. I've already checked the balancer against TDC, and when #1 hits the top of it's travel, the line is dead nuts 0. Also the rotor is lined up with #1 cyl. Now is it even possible that I put the cam in wrong, like a tooth or two off in relation to the crank? Bear in mind that it starts right up, and runs pretty well, except for not breathing fire. If not the cam, how the heck is it at 35for base timing?
At this point, I'm ready to tear apart the motor and start over, but would really appreciate any help or advice before I do.

rustyroger

I'm not sure if I'm reading your post correctly, 35 degrees total timing @3000 rpm sounds about right, initial (idling) timing should be around 0-12 degrees depending on your particular engine.

Your timing should advance as engine speed increases, easy to check with a strobe light. It's quite possible the advance mechanism has frozen over time which would certainly give you aenemic performance. The vacuum advance might well be not working anymore either which would give similar symptoms although not as bad.

Worth checking before you start tearing down your engine IMO.

I'm not trying to teach Grandma to suck eggs, I have been earning a living wrenching most of my adult life and learn something new all the time.

Bear in mind modern cars have much better performance than the smog engines of 23 years ago, your car might be as good as it ever was, but modern cars have a lot more zip in comparisom.

Roger.

jrsixx

Roger, no it's actually 35 degrees at idle, with a dial back timing light. I have no idea what it gets to at 3K. The thing is it doesn't run like it has 35 degrees initial timing, no pinging, starts fine, it just has no *****. Not sure I get the grandma sucking eggs reference, but I agree with learning something new all the time. Almost 30 years doing this for a living and as soon as I say I've seen it all, something comes up to prove me wrong.

captjim

A very common problem with 350 builds is the replacement pistons. If you have the 23cc dished pistons that are sitting .045 down with a thick replacement gasket, your Cr will be around 7.8 to 1. Any cam will make it worse. My wife had a 77 442 clone that had a re-ringed 350, 8.6 to 1 Cr, 210/216 cam and 2.41 gears and it was fairly peppy.

Run to Rund

Did you disconnect the vacuum advance before setting timing? Do you live near anyone on CO who could help you? It is hard to diagnose from the internet.

rustyroger

"Don't try to teach your Grandma how to suck eggs" is another way of saying don't tell someone how to do their job. No offence intended, I hope none was taken.

Your timing should advance as engine speed rises (mechanical advance). Might be worth getting your timing light out again and see if that happens. Plug the vacuum advance first. If your timing is doesn't move I think you should check out the distributor for stuck weights or broken springs.
I think 35 degrees initial timing is waaaay too much for a street engine, in fact I'm surprised you dont have starting issues.

Roger.

Rickman48

You mention a 600 Holley, and I'm going to guess vacuum secondaries.
If it's 'box stock', I'm gonna suggest you get the performance kit for it and change the secondary spring to the black spring, which is the lightest, and maybe the next size up squirter.
If it's single inlet, you've whats called a 'jet plate' in the secondaries - go 2 sizes up on that.
Most Holley carbs are set-up pretty generic for stock applications, and a little 'tweaking' can really wake-up the motor.

jrsixx

Well part of the problem is I'm an idiot. I was checking the timing with the vac advance connected. I rechecked it today with it off, and i'm at about 20 degrees at idle up to about 30-35 at somewhere around 3K. Glad I did that again before tearing into the motor. I played with the mixture screws a bit and it seems to run better, still not the beast I was looking for, but maybe with rickman's help it will be. Thanks to all who had suggestions, and Roger no offense taken at all. I told you guys I've been wrenching 30 years and can still make dumbass mistakes. Now for some Holley school.....

jrsixx

Rickman....Looking on the Holley site, the black spring is the heaviest, yellow the lightest. Does that sound right? Also do you happen to know what they come with out of the box? Also can't seem to find a "jet plate" would that be the secondary metering plate? if so, how do I know what would be 2 sizes up? Really hoping a little tweaking goes a long way. You ever get by Downers Grove?

rustyroger

Hands up everyone who never made a dumb mistake (I'm standing on mine right now)

Roger.

jrsixx

OK finally had time to dig in a bit. I decided to go back to square one in setting up the carb. Made some adjustments to the accel pump arm, and readjusted the mixture. Runs a bit better, then I decided to see how open the throttle was actually getting at WOT. Fully to the floor, about 60% open! DOH! Pulled carb, drilled out throttle cable mounting hole and moved it about an inch forward. Full throttle, and instantly roasted tires. Thanks for the help guys.