I’ve been debating camming my small block for awhile now. She’s a bit old but a trooper nonetheless. I’m contemplating doing a rebuild soon but was wondering what kind of lift and duration I can run on stock heads? I really like the sound of the 292 cams with the .501 lift however I hear the stock 350s can only do about .480 lift. Does going over that risk hitting the pistons or will the flat tappet cams even last that long? Looking to spend less than $700 on a complete camshaft kit so rockers, plush rods, timing chain and gears, etc
What are you wanting? A engine that goes "Rump Rump Rump" when idling , A top end screamer, Or a Torque monster. For a pickup I would recommend this [ELGE1029P] Only $155 plus lifters and a cheap set of "drop-in" Z28 springs https://www.competitionproducts.com...214-050-443_443-112-LC/productinfo/ELGE1029P/ Elgin, Hydraulic Flat Tappet Camshaft For Chevrolet Small Block, Duration 214°/214° @ .050 Lift .443" / .443" LSA 112° Later when you do the rebuild, get some cheap junkyard iron Vortec heads and install new valve guide seals properly and ^^^ cam will work [Vortec's need machining for higher lift] And use a cheap "Summit Racing" dual plane intake with the Vortecs https://www.summitracing.com/parts/sum-226062
if you go this route you will also need new valve covers or adaptors to run your covers. Not a big deal but one more thing to consider.
What is the C.R. of your engine? A 70s smog motor with dished pistons and 76 cc combustion chamber heads can't use a performance camshaft. MY point: you maybe should do the rebuild and pick appropriate parts then. Pull a valve cover and get the head casting number.
Vortec heads and a cam with a duration around 206-214 @ .050 will still idle nicely and have a bunch more power. Better gas milieage too. You'll likely need to get a new intake to use those heads, though.
My 66 Suburbans' 350 engine had a Comp Cams "268" (older) cam in it when I first put it together, was only 9-9.5/1 compression but it really ran good, sounded nice idling too. Got the itch to do some upgrades on it with Edelbrock aluminum heads and cam change. I originally wanted to go with Comps' "292" but realized the engine probably would not support it so chose their "280" cam, have yet to refire the engine but I expect it to be a good middle of the list cam choice.
Back in the day,,,early 80’s,,,,,Comp had a really nice hydraulic cam that was .525-.525 . It worked great in a 350,,,,,,had a ton of power for what it was . Never gave any problems with valve to piston contact ,,,,,,,there were many around here that ran them . Worked great with stock rockers too,,,,,,if you use stock rockers,,,,,elongate the slot about .050 or so,,,,,just to be sure and have enough rocker travel . For your present application,,,,I would do the cam and lifters,,,and timing set . The rest will be fine as is . oh yeah,,,I’m not recommending the .525 for your application,,,,,,,I’m just saying that a smaller cam should clear the pistons just fine . Tommy
https://www.summitracing.com/parts/sum-k1103 Some “z28” valve springs and a timing chain and some gaskets
The main problem with a cam that has .500" or more lift is the possibility of the press in rocker studs pulling out. If you have screw it stud's you should be good to go.
There's nothing that states you can't go over .500" lift in a SBC 350, but as mentioned once you go over around .480" lift I'd go to screw in studs. Valve covers don't need to be replaced for higher lift cams, unless you go to full roller rockers. Stock rockers, or stamped steel roller tip rockers clear and fit under stock valve covers. Even with .530"/.535" lift on my roller cam, with roller tip rockers the low height valve covers fit. Flat top, or dished top pistons wont usually cause valve to piston interference, at least I haven't had any issues. I've got flat tops, with the .530"/.535" lift, and Dart SHP 180 heads, and plenty of clearance. I highly recommend Howard's Cams as they've been very good assisting me in selecting the right camshaft for the engine, drivetrain, and how my car would used. The only company that actually had a tech who didn't want me to go to their website, and get me off the phone quickly.
I thought the same thing too then came to the realization that the poster was most likely talking about another posters suggestion to swap to Vortec heads as in ... "if you install Vortec heads you will also need different valve covers". Copy/pasted "Later when you do the rebuild, get some cheap junkyard iron Vortec heads and install new valve guide seals properly and ^^^ cam will work [Vortec's need machining for higher lift] And use a cheap "Summit Racing" dual plane intake with the Vortecs" then ... "if you go this route you will also need new valve covers or adaptors to run your covers".
I personally can't handle the center bolt head looks, so would have to buy adapters to use perimeter bolt valve covers.
For a nice driver stay on the mild side. I have had good results in mild 350's with the Crane 266/440 cam (an old Cam Dynamics grind)-have used many. Good mid range etc. Elgin has a similar grind as well.
I'm thinking that some Monzas came with a 305 as well. On the topic of 305 Chevys, a pair of 416 or 621 heads off of a 305 have (I believe) 58 CC chambers so on a 350 they would be a cheap way of bumping compression. I think it's the 416's that are preferred with the intake valve less shrouded by the combustion chamber shape. Some will say nix to the 305 heads, but for a street, mildly warmed up SBC I see nothing wrong with them. They're usually available for small $$. Lynn
Maybe you missed the 70s and 80s. Everyone was re-camming the turd compression Small Block Chevys. Stab in a L-79 camshaft or a Summit Racing SUM-1065 call it a day.
If the truck is your everyday driver, I'd consider finding another used 350 engine and do your rebuild. While you are doing that you can actually check how much valve clearance you can use with the pistons you choose. Nobody can really tell you what cam will work in an old engine of questionable origin. Even if it came from a Monza, you don't know that its got the original pistons. You can buy one of those inexpensive tools that let you remove the valve springs with the heads still in place. Set the engine at TDC and rotate it about 10 degrees BTDC and let the valves down till they touch the piston. Then put a dial indicator on each valve stem and pull up till they seat. That reading will give you a good idea how far your valves can open (lift) before they hit the piston. Then raise the valves and rotate the engine to 10 degrees ATDC and check the valves at that point. Now that you know how far it is to make contact with the piston, allow some clearance. Get stronger valve springs with sufficient travel to handle that movement. Get some roller rocker arms (1.6 ratio ?) that will give you the lift and piston clearance with the cam you choose. Still, I think you would come out better by building another engine and just swapping them when done. That way if you have a problem you can reinstall the original. If not, you can sell the engine you have.
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