Originally Posted by andrewakessler
I'm looking to upgrade the heads on my 350 SBC (mid 70's) to a Vortec design (part: 12558060). I know I'll have to buy a new intake manifold, but would I be able to run my stock cam on this setup?
The truck is going to be a street rod. Not looking to race at the track, and I'm not looking to eek every ounce of HP out of the engine.
If this cam won't work, does anyone have a good secondary option that won't break the bank?
Thanks in advance,
It depends on what level of power you want, up to 300 horses will be a mild cam that will run with the factory valve springs. 400 horses will take a more aggressive cam with matching springs with 1.6 to 1 ratio rockers and some porting work with a good intake like the Edlebrock Perfrormenr RPM and a carb with around 700 cfm capacity, good long tube headers and good dual exhaust. 300 horses is pretty easy to obtain with decent factory intake and 600 CFM carb, 1.5 rockers and a cam similar to the old 300 horse 327.
The Vortec head doesn't care about the cam other than it has a limit on lift at the valve which should be considered .450 inch till you actually measure the head you have as some will go to .470 but I wouldn't assume any and every one of them will do that. The spring is 1.25 inch diameter, there are kits that let you run more pressure if needed for a bigger cam like the Comp XE268 if you're shooting for 400 or more.
The Vortec head will be happy with your stock cam and will deliver around 250-260 hp with the typical pre L31 Vortec OEM truck cam and short block.
The L31 head does not have cast-in push rod guides like the older heads, it is designed to use self-guiding rockers. It can be converted to traditional push rod guiding with after market steel guides but these require the use of screw in rocker studs which also require the stud bosses be milled and tapped, so you get to decide what configuration you want to spend your money on. The least expensive option, especially if you're retaining the engine's original cam is to use the OEM sliding contact self-guided rockers.
So you've got some options you need to work through to see what fit your desires and budget.