I have a mild build 350, that I feel doesn't have the power it should have. It's a 73 block, stock dish pistons, stock rods, stock crank, the can I was told is just one step up from stock, flat tappet lifters, 69 #5 heads, edel proformer intake, with a 625 cfm single inlet carb. The engine was all gone through and freshened up. If I pin it to the boards I can get a little chirp out of the tires and it takes off but I feel like there should be more there, any ideas on what to check or anything I should change. Also is 20 degreese of base timing seem like a lot to anyone?

 

What dist. are you running?

 

It's out of an early 80s 350, vacuum advance.

 

Well, first off, what sort of "stock dish" pistons are they? 14cc or 23cc?

14cc was stock for the '73 (with #8 heads), but 23cc is usually sold as a generic "stock" piston.

If you have 23cc pistons with #5 heads, and a standard FelPro head gasket, you've got somewhere between 7 and 7.5:1 compression, which, with a cam that's "one step up," would be a dog.

20° timing at idle with vacuum advance disconnected is about normal for an HEI distributor, though the thing to check is whether the mechanical advance is topping out at about 35° at about 3,000 RPM.

- Eric

 

88olds350, did you degree the cam, or just line up the dots?

Your cam may be way off?? What is your cranking compression, as this may give a clue.

 

thar distributer might be for a CCC system. most 80's distributers were, how many wires, plugs are on the dist? 20* seams a lot, what carb port do you have the advance pluged into? lets see a pic of it. ya cant trust most chevy guys building an olds

 

What gears in the rear end? Does it have a posi?

 

I thought this thread was about being married.

 

Lmfao z11. To the op. What rear gears what converter. I had a similar set up with an hei 14 degrees initial running 13.8's in the 1\4 mile. That engine is now in my dads car and has 2.73 gears and it's now a dog. Going to add 3.23's . I originally ran 3.42 gears and it would light em up like no ones bbuisness.

 

He did say it has vacuum advance. If it does, it can't be computer controlled.

If the pistons are stock with #5 heads, cr should be decent, mid 8.xx to 1, even with a fat gasket If the engine was bored and pistons replaced, motre like 7.5 to 1 as Eric stated. If the cranking compression is around 160 +/- it is probably in the tune. If it is low, 120 +/-, you know it is either in the build or the cam is off. It would REALLY help to have the specs.

 

Get a timing light, see where your at now, both initial & mechanical advance. Don't worry about the vacuum advance just now.
Hook up a vacuum gauge to the manifold & drive the car. Does the vacuum gauge drop to zero at wot? If it doesn't then the carb is too small. Olds 350s do well with 750 QJs.
What kind of exhaust is on the car? Duals with manifolds is a good starting point, headers are even better.

 

That has nothing to do with his problem. He didn't say it started out strong then fell on it's face. He mentioned it was a pig from the start. If the carb was too small it would be responsive down low but then fall off.
As mentioned check the basics, then go from there.

And technically there really isn't a cam that's "one step up from stock". That's just as bad as saying it's a 3/4 race cam.

 

Unfortunately I believe Eric kinda nailed it. Can you find out a bit more detail on your build that would guide us to an informed opinion. What pistons and cam would help dramatically. If not perhaps a compression test to see how much pressure your cylinders are running.

 

Sorry I haven't gotten back to you guys sooner. The distributed isn't the computer controlled one, it's an HEI with vacuum advance, rear gears are stock to the car, I believe 2.73s? Limited slip. I wish I knew more about the cam but the machine shop did the whole short block, Its most likely out in with just the dots lining up, not degreed in . Exhaust is 2 1/2 true dual off iron manifolds. I've been looking into headers but I have a feeling I'm going to run into space problems. I'll get more info dealing with compression probably close to the spring of the year, it's too cold to do any work on it now in New York.

 

Well, I got a LOT better power out of a high compression 403 with HEI after advancing the timing to 36 max, then limiting the vacuum advance to 10 or 11 degrees (adjustable vacuum can, readily available) and to solve the tough start issue, connect vacuum can to manifold vacuum.

Voila'

timing around 10 for easy starting
at idle, ~10 more from the vacuum for great throttle response and [edit] NO overheating
at WOT, ~36 total for best results there.

 

How did you do this Octania? When you have around 17 deg's of mechanical advance built in to an HEI, + 10 deg's initial,+ 10 or 11 deg's vacuum, = 20 to 21 degrees at idle with vacuum connected and only 37-38 at light cruise. Then at WOT you only have 27 total mechanical. I don't think that works very well for performance and/or fuel economy.

 

Also check that the carb opens all the way. My 72 350 Q-jet had a repaired trans kick down(shorter) and a modified accelerator cable so it would "work". Also, the bracket on the rear of the carb that holds the accelerator cable was bent. I was getting ZERO secondary opening and not even full primaries. Thanks previous owner!

 

One simple way is to install a Moroso HEI Advance Curve Kit. The center bar and weights with this particular kit give 24º mechanical advance, so you can set the initial to 10-12 to get 34-36 total.

 

Yeah, what he said
I had the entire write up on ROP but after the last crash and loss of membership, it's a wasteland. I can't bring myself to redo it AGAIN unless there's a way I can back it up myself. I had all kinds of photos, how to measure with your homemade tools, how to modify, what the results were, etc.

Also the entire learning process and toolage and suppliers for parts and grease to rebush and revive the UHV pointless distributors.

 

It was my assumption that all you did is add a new vacuum advance and set everything as I said in my example. Thanks for clarification. I prefer getting as much initial and limiting the mechanical for low end torque. Everyone has their ways.