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Discussion Starter · #1 ·
I picked up a tired old 350 (for my <cough> Camaro) and I'm trying to decide how to build it.

Quick backstory: non-original tired 350 in the car currently, while tracking down an oil leak I found the front pan seal was twisted, and replacing the pan gaskets would basically require most of the work needed to pull the engine. Also, it's an aftermarket cheapie chrome pan that PO installed, so my chances of getting it to seal properly are pretty low. I did The Wrong Thing and slathered the whole front chin of the engine with RTV, and that seems to have at least slowed the leak down for now.

While searching craigslist for "oil pan", I found a "complete intake to oil pan" 350 for cheap. I figured I could redo this one and swap it in when it's ready, and still be able to drive the car in the meantime. Bought it: 1975 1-ton truck code, 991 heads, turns over by hand, looks fairly tired and sad, but I know nothing else about it as I haven't taken it apart yet.

I don't want an LSx, don't go there.
I don't want a hairy-edge lumpy race engine.
What I do want is a reliable cruiser.

Thinking of trying just a super low budget rebuild, ball-hone the cylinders, new rings, bearings, and gaskets, oil pump, timing chain, RV cam and lifters, lap the valves, new valve seals, maybe valve springs too, and throw it back together again. Assuming there's not a big ridge at the top of the cylinders, and no other surprises.

Am I crazy? My biggest concern is the valves/heads. There doesn't seem to be a cheap new solution for heads, and I'm not sure just lapping the values will do it.

Ideas?

Thanks!

Motor vehicle Wood Gas Road surface Automotive exterior
 

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I picked up a tired old 350 (for my <cough> Camaro) and I'm trying to decide how to build it.

Quick backstory: non-original tired 350 in the car currently, while tracking down an oil leak I found the front pan seal was twisted, and replacing the pan gaskets would basically require most of the work needed to pull the engine. Also, it's an aftermarket cheapie chrome pan that PO installed, so my chances of getting it to seal properly are pretty low. I did The Wrong Thing and slathered the whole front chin of the engine with RTV, and that seems to have at least slowed the leak down for now.

While searching craigslist for "oil pan", I found a "complete intake to oil pan" 350 for cheap. I figured I could redo this one and swap it in when it's ready, and still be able to drive the car in the meantime. Bought it: 1975 1-ton truck code, 991 heads, turns over by hand, looks fairly tired and sad, but I know nothing else about it as I haven't taken it apart yet.

I don't want an LSx, don't go there.
I don't want a hairy-edge lumpy race engine.
What I do want is a reliable cruiser.

Thinking of trying just a super low budget rebuild, ball-hone the cylinders, new rings, bearings, and gaskets, oil pump, timing chain, RV cam and lifters, lap the valves, new valve seals, maybe valve springs too, and throw it back together again. Assuming there's not a big ridge at the top of the cylinders, and no other surprises.

Am I crazy? My biggest concern is the valves/heads. There doesn't seem to be a cheap new solution for heads, and I'm not sure just lapping the values will do it.

Ideas?

Thanks!

View attachment 445295
what year Camaro? transmission? rear end? gears?
 

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I only ask because I am curious how much power you want... 300hp? That's easily obtainable with those heads, the right cam and the correct piston. If you find out the piston in it (stock or some old replacements), that would help narrow down what you can do with it without many other parts. A good stone hone (don't use a dingleball hone as it does not typically take care of cylinder wall taper at all and only adds to the issues of ring sealing), some good quality rings (broken in correctly without running too rich), some headers, carb, manifold and a decent RV cam and you should be able to get there under $5-600 if you source parts from CL or FBM... lots of used parts out there. I have a ton of old SBC performer manifolds, just gave a speed pro performer RPM copy mani away to a guy who needed one. 991 heads are if memory serves me correctly 75cc with a pretty small intake/exhaust runner and a crap comb chamber but they can still make 300 easily... but likely not much more than that due to volumetric efficiency and air flow. garbage in-garbage out. You can only pump so much air through a given orifice and depending on the shape and configuration of both the runner and the port surface, not a lot to be done on those. Maybe someone else has more info on that head but, if you're only looking for a solid street engine that won't be maintenance-intense and unreliable, you can build a fair engine from that setup. The quadrapuke manifold needs to go though... choke city
 

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Mine works really nice for cruising...well mannered with nice low to mid range tq (about 385 ft lbs max)...about 360 hp. Stock L82 short block with summit cast iron heads (dart Iron Eagle) and Howard's Street Force 2 HYD flat tappet... .455/.465 lift. I did just what you are proposing with rebuilding the short block and added the heads and cam. Also an Edelbrock 2101 intake w/ 600 carb and long tube headers.... 3.73 rear...
 

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Discussion Starter · #6 ·
68 Camaro, TH350, 3.08 rear gears. All the details here: Pat's Car Blog – And other random info

Yeah, 991 heads are awful, but that's what is on it now. I feel like getting some better used heads off CL is going to get me something that's been beat on and will need more than just lapping the valves. 300hp is fine, not really looking to burn up the dragstrip, mostly just want something reliable and fun to drive on the street...hence the RV cam. I have a performer intake, HEI, Holley 600 VS, and headers that I'll reuse from the existing setup.
 

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68 Camaro, TH350, 3.08 rear gears. All the details here: Pat's Car Blog – And other random info

Yeah, 991 heads are awful, but that's what is on it now. I feel like getting some better used heads off CL is going to get me something that's been beat on and will need more than just lapping the valves. 300hp is fine, not really looking to burn up the dragstrip, mostly just want something reliable and fun to drive on the street...hence the RV cam. I have a performer intake, HEI, Holley 600 VS, and headers that I'll reuse from the existing setup.
you're already halfway there if not 3/4 the way with all that. Those heads should get you 300 if you get the right cam, and new springs. Find out what pistons are in it and then you can figure your compression out for the right cam choice with those heads. Plenty of cams to choose from, just finding one with the right lifters that won't break the bank and /or lose a lobe on break in...

Good cam choice video here:
 

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Discussion Starter · #10 ·
TXD is the application code, that translates to

TXD
1975350conv.cabL LS91654C-20 to 3500

A good stone hone (don't use a dingleball hone as it does not typically take care of cylinder wall taper at all and only adds to the issues of ring sealing)
Interesting that you recommend a stone hone instead of a ball hone, I just assumed a ball hone was the way to go. Good to know...

Trying to avoid getting stuck in line at the engine shop and DIY instead.
 

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so 165 hp 4-barrel 350. may be a 4-bolt, may not. Probably dished as @bracketchev70 stated unless it's been rebuilt in the past and being a '75, very well could have been with some 4-valve relief pistons. You really gotta know the internals before you start planning but you have a good bunch of parts already so you're on your way. Get a head off and check the piston out. If the pan can come off easily, you may be able to see some markings on the underside of a piston from below and find out what it is exactly... maybe not. worth a try... or just slide one of those rod/pistons out and take a look. Check piston to finished deck height... the works.
 

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Discussion Starter · #12 ·
My last build was the engine for the Nova, and that was fairly stout (406, forged, Dart Pro 1, solid roller) but I got tired of driving it on the street as it was not street-friendly. I've moved a couple of times since I did that build, and have to re-buy an engine crane and and engine stand before I get too far into this one. It's in a cradle now, and I can pull the heads to check (or maybe get a camera in the spark plug hole) but I haven't gotten that far yet. Still on the drawing board.

Good to know I'm not too crazy though, it's sounding doable.

Thanks for the replies everyone!
 

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a stone hone instead of a ball hone
Many people use a ball hone and if the cylinder is perfect, then it won't cause much issue. If you have a ring ridge, you need to cut that first then hit the cylinder with a good stone hone, in differing grit increments to get the cylinder back to some relative shape without much taper or at least as much as prior to the ring ridge reaming. Uncle Tony (Tony DeFeo from Cars Illustrated and other hotrod rags) has a good description of why you want to use a stone hone on an old bore here:


And:

 

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Discussion Starter · #14 ·
Yeah, pretty sure this one does not have perfect cylinders. Then again the intake is RTV'ed on, so the engine has been apart at least that far before, so who knows. Buying it was a total gamble, all I know is it isn't seized.

Worst case I send it to machine shop jail and have them do it .030 over, and make a 383, but that'll take more time and $$ than I have now.
 

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Yeah, pretty sure this one does not have perfect cylinders. Then again the intake is RTV'ed on, so the engine has been apart at least that far before, so who knows. Buying it was a total gamble, all I know is it isn't seized.

Worst case I send it to machine shop jail and have them do it .030 over, and make a 383, but that'll take more time and $$ than I have now.
Well, check it out. you may have gotten a good starting block (pun intended) and you hopefully won't have much more than a good freshen up with a cam, timing set, bearings, rings and gaskets, valve seals and maybe a solid lapping... possibly some springs.
 

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Usually cheap and engine rebuilds don't need to be used in the same conversation. If I couldn't afford or didn't want to spend the money to do everything at once I would do it in stages until I could build a decent engine. You don't have to spend a ton but I would certainly try to spend my money in the right places.

I always start by taking the block to a machine shop to be cleaned, checked for cracks and new cam bearing and freeze plugs. You may also find out that it needs boring. At the very least I resize the big end of the rods and put a good rod bolt in. At the very minimum I would want a flat top piston. If I had to buy pistons and resized the rods I would also have it balanced. If I had to quit right there until I could go on I would but my short block would be ready. It would be built to last and could provide decent HP numbers. You are already going to have to buy rings, bearings, oil pump and such so they wouldn't be any more expensive.

Even if I had to wait I would buy a aftermarket head if it wasn't anything but a vortec. You would be worlds better off with them over the smog head you have now and in the end there wouldn't be much more expense if you had your heads built and you would have a new head with a lot better design.

A decent camshaft and intake and you are all set. You could probably easily build this engine for under 1500 and it would last forever and everything would be fresh.
 

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When you get around to buying the Cam, do not buy a cheap cam. or lifters, and check the lifters to be sure they "rock" a bit. Apparently some are being manufactured flat on the bottom and wont spin, thus wiping out the cam. OR just go roller lifters.
 

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You're not crazy at all. I literally did the exact same build a few years ago with leftover parts and a very "well-seasoned" 400 small block, tired 291 heads, and a shmedium-sized flat tappet cam. It's still in my car and providing smiles to this day. The bearings are junk, the quench sucks, and it is no fire-breather. But boy howdy does it make me smile.

Going off of my experience, I would suggest getting the engine on the stand and doing a careful deconstruction of it first and foremost. Take note if worn rocker arms, lifters, pushrod ends, etc. If it all looks good, and the cylinder walls don't look super worn out... You may be able to just send it.

Take a peek in my build thread, starting at this post. It explains the steps I took for my "combo", which is carefully curated garbage with some specific parts to make it all work.
 
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