Technical Performance suggestions, including carb choice?

I have a sbc 350 paired with a th350 in my 51 Mercury.
I am told it has a mild cam (and it sounds like it).
I don't know the cam specs or any other engine specs.

This will be a daily driver, but I'd like it to have some oomph too.

Holley 80457-7 carburetor
Edelbrock performer rpm intake
Taylor 409 10.4mm wire set
Basic HEI distributor
NGK shorty plugs
Flowtech headers

What would everyone recommend I add (or remove) to my setup?

I have other parts available that I've gotten in trades:
Mallory Comp 9000 distributor
"Angled plug" heads
Roller rockers
Holley 4776-6 carburetor


Be patient with any stupidity I may convey. I am learning as I go....but I'm a quick learner.

 

Did I post this in the wrong section?

 

It should oomph pretty good as it is. Have you tuned it well, compression check, timing, jetting? What is the rear end gearing?

 

For a heavy car, and a daily driver you want a mild, high torque motor. Basically stock with a mild cam, headers, and single 4 barrel.

If the budget will stand it a 383 conversion (long stroke crank) might give more usable power boost than aftermarket heads.

Not being a Chev expert I can't give you part numbers or anything like that. But if it was mine, that is the direction I would be going.

 

I'd go with the plain 'Performer' intake as it's optimized for lower-rpm use; with a heavy car and a standard-stall convertor auto trans, it will give more low-end grunt. Unless you plan on spinning the motor above 5000 rpm, the RPM version will hurt the low end.

 

I haven't done any of that yet. I figured I'd put everything on there that was going on, then tune everything.
No idea on rear end.

 

Sounds like I'm on the right track then. Thanks!

 

Ok thank you. I'll look at downgrading once I can afford to.

 

Suggest you start with a compression test and oil pressure test. If they prove out good, perhaps a tuneup is in order and you are good to go. Not much sense in tearing into a good motor.

Did you just buy the car? It appears someone has spent some money on the motor, it may be newly rebuilt for all you know?

 

I just bought it a couple of months ago, yes.
I changed out a rattling water pump, cracked fuel filter, bad alternator, plugs/wires, paper air filter, and entire wiring harness. Everything else I've done was dress-up stuff that I had laying around.

 

Horny.

I've read those Mercs aren't as heavy as they look.

 

Yeah. Stock horns to pass inspection.
Air horns just cuz. [emoji12]

3550lbs

 

Spend your money on a wide band o2 with a gauge and tune the hell out of what you have. I would be willing to bet if it went on a dyno and was tuned you would find 50hp over the baseline with just tuning

 

Hi,
You have a good basic combination there, probably just needs tuning. First work with the HEI distributor, get a hot coil and module and change the centrifugal advance to more initial like 14-16 degrees and less centrifugal in the distributor, look on youtube for some videos on how to do this. This will add some low end torque. Once that is done a dyno tune or buy a wide band as recommended above and get the jetting right. Will make a big difference.

 

Well those were with at least 800 horse power. I have been looking for some thousand horsepower lights for my Harley myself.

Do the Eddy intake and a Holley 1850 600 CFM carb on any unknown small block. Can't go wrong, well I wouldn't use the Eddy but I am an odd duck.

I am not a fan of HEI but if you go with an advance curve kit and use the middle springs it helps a stockish 350.

I like angle plug heads but they need a little help in the port dept for anything that I would build. They would probably work for your car as is. You may find it difficult to change plugs depending on how close your headers fit.

If you have roller rockers as in roller fulcrum rockers I would run them I probably wouldn't take the time to put on roller tipped stamped steel rockers but again I am an odd duck.

I don't know what constitutes a mild cam. That has followed the same road as RV cam these days it is a catch all for any cheap off brand cam someone decides to use when they build the motor. So I really can't help you much there.

Probably the best thing you could do without getting into it and seeing what it is and making changes from there is tune it to the max and drive it.

 

You've got a great baseline-I don't even think id' worry about the Perf RPM intake- It wont kill too much off the bottom end at all on a 350 with a close-to-stock cam.- since you own it-run it. What's the rear gear? -give it a bit more gear- More gear will REALLY wake her up, but don't go nuts if you like to cruise highways. -rick

 

I have no idea how to find out rear gearing.

 

On one of the axle tubes you will find a three digit code number stamped in the metal. This code will give you the FACTORY ratio. However you will need to jack up your rear end, put it in neutral, and mark your drive shaft with a chalk line. Then rotate both rear tires together (unless it is a posi) and count the number of times the drive shaft rotates. 4 times, you have a 390 or 4.11, 3 times you have a 3:08.
A good tune up will add around 25 HP. right plugs, quick mechanical advance, working vacuum advance, good gas.

 

Rear gearing even for a daily, given you want some giddy up, is very important. I usually gear cars with similar setups as yours with 3.73's and a posi. Enough mechanical leverage to get it up and moving off the line without high revving at 65mph. This is where I'd upgrade first depending on what you have currently. And FWIW, a .5 deeper change in rear gear ratio will make the car feel like it picked up 100hp.

I'd personally stick with that intake if it were mine. I've had a lot of success with their rpm intake/cam combos in mild sbc's. Advance curve kit as stated in that HEI, a quality shift kit in the TH350 can not only quicken up the car by decreasing the shift lag (time between shifts as it slides into the next gear) but lengthen the life of your tranny's clutches because instead of slipping they are grabbing quicker. It does make the shifts firmer so its a personal choice. Most shift kits you can do in your garage in an afternoon yourself.

Be sure all 4 barrels are opening fully when you're on it. Check linkage...

Good luck with it. sounds like a neat car.

 

This is all great advice, guys! Thank you!

 

Incidentally, all the other stuff I don't use will be up for sale as soon as I can post in classifieds.

 

What heads are on it now (casting numbers), and what are the angle plugs.

Get an advance kit for the distributor, stock hei's have a very lazy curve for smog motors, tune the timing and carb. sounds like you already did plugs and wires.

 

Better bang for the buck might be a th200-4 or 700-4R .lower first gear and tighter percentages between shifts will make what you have more efficient.
Overdrive will like the torque your combo has.
Pretty much as you make more hp you have to put the motor In a higher operating range,and bottom end power is usually sacrificed.
You have a decent baseline,now fine tune it.
Good luck,
Gary

 

These read 8898998 (I think) with 312 beneath that. Let me know if these are the wrong numbers.


I'll get the numbers off of the others when i get home.

Hei only has vacuum advance as far as I know.
Plugs are NGK Vpower shorties.
Wires are 10.4mm Taylor 409s

 

Here's what's stamped on the angled plug heads...

 

Trying to decifer your numbers. Are 3986339 3986388 possibilities? If so these are 307 or 350 1.72 valve heads. The engine may be a 307 and that would explain general lack of power. 307's can be made to run and are great driver engines, I wouldn't chuck it if you find out it is a 307.
If these are 1.72 valve heads you just aren't gonna make much power with them.

Take a better look at the numbers and match the up here.
http://www.nastyz28.com/sbchevy/sbch.php

Any info on the angle plug heads as well.

 

I'll try to look more closely at the numbers.
It will be frustrating if I was lied to about the engine size.

Angled plug head info is above your post.

 

Just saw your post. If the angle plugs don't have casting numbers between the valve springs, they may be aftermarket heads. VERY INTERESTING.

 

Found this link, you may have a set of world products aftermarket heads. If so, these are the way to go.

Verify if the engine is a 350 or 307.

http://www.stevesnovasite.com/forums/archive/index.php/t-164396.html