have a very original '72 that I would like to keep as stock as possible. The base 350 engine now has over 200,000 miles on it. it was rebuilt over 20 years ago at 117,000 miles. it was bored .030 over. stock gm 3896962 cam, stock q-jet, stock intake, stock manifold, & stock heads. It is getting a little tired so want to start thinking about another rebuild. I don't know anything about engines, so i would be getting everything done at a shop. i'm assuming it can take another rebuild on the block at .060 over.
The one thing i would like is a little more power. not anything crazy.
would like at least 300hp at the wheels.
what advice would you give me with the above details. i do not want to put on headers, as they would compromise my collector plates i have now.
of course, i want to spend as little $ as possible, but since i will be rebuilding it, it would make sense to do any upgrades at this time.
any advice greatly appreciated!

 

I used that 962 cam in my last hot rod - a '70 Nova running a Turbo 400 and 4:11 twelve-bolt Posi rear. What a rocket ship that car ran like! My 350+ would smoke 'em easily and stay at 6500 until I shifted or got tired of the smoking tires.

I would stay with that cam (but new if it's still avail) but add induction and exhaust to the equations.

If you want a stroker, that cam isn't the right one for a stroker but ther''s lots of choices out there. Use aluminum heads, 2.05 stainless valves and have the intake port matched to the heads.

Make sure you get it balanced no matter what. Use a completely forged bottom end if you can afford it.

Or just get a zz383 from the dealer and have some fun!

 

Carefully inspect all the components you remove in disassembly for any indications of excessive and/or unusual wear patterns , paying particular attention to the block and crank , excessive crank endplay , stripped bolt holes , loose main cap registers , excessive wear in the lifter bores , crank run-out. Have the bare block accurately gauged for diameter and cylinder taper , and see if the block can be cleaned up and finished at .040" over , rather than automatically going for a .060" overbore. This will minimize any potential problems arising from core shift in the block casting, and be sure to have the block at least magnafluxed before investing any money in machining.

At today's machine shop prices, I believe it's more cost effective to buy good aftermarket rods with good hardware , rather than paying to check the old rods for cracks and flaws, twist , and then resized with good ARP rod bolts , which also shortens the rod length.

As for heads , if $$ are very tight , Summit has good quality cast iron heads available for about the cost of rebuilding your originals , or you might want to consider using the newer Vortec heads with a Performer or Performer RPM intake , which would be an improvement over the original intake in either case.

Most important is your selection of a competent and honest machinist , who will actually do the work he's paid to do , since you indicate that you will have to rely on him to evaluate , measure , machine , and assemble the motor. Ask around at the local cruise nights in your area for recommendations - ask enough people , and the best shop should reveal itself by satisfied customer recommendations. Then go and talk to the machinist at his place of business , and note the cleanliness and organization of his shop , and determine if he's interested in building what you want built , or wants you to buy what he would rather build.
On that same note , I've noticed over many years that the guys who brag about themselves the most usually don't produce anything worth bragging about.

Keep us posted on your progress.

 

If you are going to bore the block, it is time for the stroker crank. Best bang for the buck when you figure in all the costs. You get a lot more bottom end that way. Just what a stock C3 needs. You are already into a new set of pistons anyway so the incremental cost is small.

The heads are also a great place to pick up power for low bucks. You save the cost of rebuilding the heads and you get all new parts + power too. The iron heads that summit sells are probably the best bargain for this application. You can keep the rest stock. Curve the distributor too.

That "962" cam is still available from several sources. I installed that one in my car with upgraded heads and it performs well with plenty of high RPM range available. If you combine these upgrades with the stroker crank you will get a relaible, easy to live with torque monster. Keep the C/R around 10.4 or so and you can still run the pump gas with that cam.


-Mark.

 

so lets say i go with your advice on the stroker route. new bottom and top end parts including new summit heads and new intake as described. with machining and parts, approximately, how much should i expect to pay? i would thing i could stick with my q-jet carb, which i like, and old points distributor, which hasn't given me any problems (tuned to Lar's recommended specs re timing etc) then, how much more would the vortec head & intake be vs iron heads and intake?

 

 

If you have the original, numbers matching block with your car and it is already .030 over I would not rebuild it again. I would save it and build another one. Core 350 motors are easy to find, and once your numbers matching block is gone-it's gone. If it is already a replacement block, I would (re)build away.

 

yes, it is definitely the original block to the car. i just thought it being the base 350, ie not an LT1, that a rebuild would be the obvious choice. why would you not rebuilt it, even if it had to be at 060 over? it is still going to last another 100,000 miles i would think, and by that time, i will very likely have sold it, and bought my dream C2 (sorry C3 nuts).

 

Per previous recommendations, methinks you should first determine if your existing block will clean up at +.040" vs. the .060" that you first suggested. and as for there being any significant difference between LT1 blocks and yours- there isn't. '72 smallblocks were all four-bolt mains; the only thing motor-wise that separated the LT-1's from the others were the solid-lifter cam, higher compression ratio and OEM Holley carb. Summit sells a hypereutectic piston rebuild kit for $239.00 that includes rings, bearings, oil pump ang Fel-Pro gaskets and can be had in a variety of compression ratios- I rebuilt my 350/300 '70 about 30,000 miles ago with one of these kits and it still purrs, and with the right cam and a decent set of aftermarket heads you should have absolutely no problems getting to 300 HP(at the flywheel) with around 9:1 compression. As far as the cost of machine work, to clean & mag the block, install cam bearings, hang the new pistons, bore & hone, polish the crank, and balance the rotating assembly should be in the neighborhood of $650-$700, so if you assemble the engine yourself you should be able to get the whole project done for between $1700-$2000. If you just gotta have the 300 number at the rear wheels, I would have to agree with stingr69's stroker recommendation, because to try and see that number with a pump-gas friendly compression ratio would cost you more money in port and valvetrain work than a low-compression stroker would, and the stroker route would give you a broader powerband with more overall torque.

 

I'm not a supporter of rebuilding/machining a block. A brandnew block with a 1-piece rear main seal which is prepped for a hyd. roller cam is only $670 at Summit...... machining your old block is almost as expensive..... just a thought

I'd keep the original block, yours may not even need a overbore (just keep it for later resale value) and put a new block with a stroker rotating assembly under the hood

... probably the cheapest way to go (HP for the $$$)