I got a 350 2-bbl in my 72 Skylark. The car is basically original. I replaced the distributor with an HEI, and other than that some changes when things broke (water pump, etc). I put dual on it with stock manifolds and it runs and sounds good. I had the tranny rebuilt about 5 years ago. My question is - while it runs fine, there are flat spots in the cam. It smells rich while running at both idle and when driving. If I tackle anything on the motor, what keeps the stock appearance while getting mechanical upgrades? I like to drive it to pick up the kids from school, go out on dinner dates, etc. Just fun - no racing, no need for massive hp gain. I'm thinking cam, timing chain, fuel pump...what else without going crazy?
If the lobes of the cam are worn, that would be an obvious thing to correct. Timing chain at the same time as well as water pump and fuel pump (the "while we're here" syndrome"). Though about rebuilding that carb? I would, but that's just me. We have several talented members that can do the quadrajet and you'll know it is done right.
Timing chain is probably a lot of the issue. You don’t mention mileage. I would suggest doing a compression test. And a leak down test. you claim tired. Or is it just weak? if compression is decent per cylinders ( Your mentioning flat spots in cam) as in performance or as in actual flat lobes? check your compression and leak down. weak valves which can be rebuilt . Carb can be rebuilt. Hei doesn’t mean much, what is your timing set to and what is max timing curve at? so assuming the short block is good enough I would go with .050 milled off heads, crower level 3 cam(50258) new lifters, valve springs, clean up porting or better yet big valves. A good dual exhaust,with x pipe, a good carb, new timing chain, a new front cam bearing. A 25-2700 small block rated torque. 3.08 or better gears. This will net 70 hp or better. And probably take 2 second of 1/4 mile times.
Along with what Brad said, I'd upgrade to a 4-bbl q-jet. It'll give you a little boost but nothing crazy. If you want to stay stock looking you can probably find a stock intake to go with it. I'd do the compression and leak down test first. Make sure you have a healthy motor to start with before you start spending money.
I agree I would start with a leak down test to find out if the cylinder head valves are sealing. You will also find out if the piston rings are sealing. ideally I would pull the engine and do new gaskets and piston rings at minimum plus a new timing set and cam.
If you're going to do anything that involves machine work or taking the engine out, my advice if you have the space would actually be to leave the running/driving engine in there and grab another Buick 350 that you can upgrade. They can usually be had for pretty cheap. This way you can still drive the car while you work on the engine. I didn't do this and my car has been sitting for 2-3 years because my engine is taking so long to finish . . . But just doing bolt-ons and an in-car cam swap shouldn't be too bad as long as you don't fall victim to the "while I'm in here" syndrome mentioned above
That actually is an excellent idea. Something I'm doing myself at the moment. But if you are getting another motor, why not just upgrade to a 455...
I wish it were that easy to find a plug-and-play 350 for cheap. Everyone always says things like that on here and I have yet to see one. It either needs a rebuild, missing accessories, or is not cheap at all. Then you have to pay shipping...and then installation. I wanted to swap a 350 into my Century to replace the 231. Cheapest running motor I found of ANY size was a 430 that was missing the exhaust for 1000. Not to mention if you aren't doing the work yourself the money to put it in there. I actually saved money by buying a cheap $800 beater to drive around while mine was being worked on.
If you don't already have one, install a high quality Oil pressure gauge and make sure you have plenty. If the engine is old, wear in the main and/or rod bearings will cause a drop in pressure. If the pressure is still good, that's an excellent sign. If it isn't, that has to be addressed first IMO. When you say your cam has flat spots, do you mean that you have visually identified this, or it just feels that way? I like the Quadrajet too, but have to warn you the "It smells rich" thing, is just how these cars are. If you don't smell some gas from the tailpipe something is wrong ;~)
I agree buy another motor and build that. I had to buy two short block to get a good core, but being local I saved on shipping. Was a good move on my part beings Covid delayed quite a few things. It’s been longer than a year now but getting close. Good luck! Build it once and do it right.
