Hello i have a 1992 camaro rs with the stock 305 and was looking to make a few upgrades and go down the road. I am thinking about the lt1/lt4 hot cam kit and put some rebuilt 350 vortec heads and tbi conversion intake on it while keeping the rest of the rotating assembly stock. how well would this work for a decent power gain. I am also going to do the ultimate tbi upgrades and a tune.

Thanks for any and all advice.

 

I would use 305 vortec heads with the casting number ending in 059. Punch the out with 1.94/1.60 valves. There are better cams than the hot cam for what you are trying to do. Personally I would run the CC304.

 

do you have a suggestion for a cam with no machining required

 

I would use the 062/906 L31 350 vortec heads. You will loose a touch of compression with them vs your heads now or the 305 vortecs.. BUT the 350 vortecs are more versatile and can be used for many years on many diff size engines with out being a limiting factor.

The 305 vortecs will suck on a 350, 383 or 400.. The 350 vortec heads will work great on those said engines. So later down the road if you wanted to do an engine swap you would still have great heads to use on it.

I do not recommend putting a lot of money into a 305... Buy parts that will work on both a 305 and a 350, as the 305 is the small block with asthma.

Everybody looks at engine parts 1st, but on these cars I recommed you start else where with your mods.

You have a 2.73 (if auto trans) or a 3.08 (if manual trans) gear.. Those suck for performance use. Put a 3.32, 3.42, or 3.73 gear in with a posi/limit slip/locker.
The seat of the pants gain of the 2.73 to 3.73 gear swap will be much more than head and cam swap together.
Plus you need the posi and the deeper gear as supporting mods for when you do make engine mods as most engine mods rises the power band up the RPM range and the high 2.73/3.08 gear makes it hard to stay in your new power band.

Put subframe connectors on the car. These cars twist bad with power and traction.

Exhaust.. Get headers on the car with good aftermarket Y pipe and cat back or custom duals. If you know you will NEVER swap to a 350 or larger engine then get headers with 1.5" tubes and 2.5" collectors.
If you think you might swap to a 350 or so engine in the next 5-8 years then go with 1-5/8" tubes, 3" collectors.

Now after those mods, look at the engine.. Do the vortec head swap, use the right springs and retainer, or grind retainers, or have heads machined for the higher lift.. use fel pro 1094 head gaskets and the fel pro MS98000T intake gasket kit.

Then add a cam... Something like
Howards #183215-10
crane #119821
comp 08-422-8
comp 08-501-8
comp 08-502-8

 

Thanks nightrider. So just to be sure that i understand you correctly if i get the comp cams 422 and buy the entire kit with matching springs etc i will not have to machine the heads for lift?

 

No.. The kit will not work out right for you with the vortec heads. Vortec heads has a clearance prob with top of valve guide to bottom of spring retainers. In stock form there is only enough clearance for around .470" lift before the retainer hits top of guide.

There's a few diff ways to fix this prob, all does the same end result. It's just how you want to get there.

You will need the comp cams beehive springs and retainers, or Crane Cam’s 10309-1 drop-in valve spring and retainer kit, or Alex's parts springs and retainers, or Milodon chrome-moly heat treated keepers that have the keyways moved up .060" inch (1.5mm) and good springs for your cam like howards 98212

Or...
you will need howards 98212 springs and do the "ghetto grind" on your stock retainers. (ghetto grind is where you grind 3/32" off the bottom of retainers. I have done this many times and it works great. My 355 in my S10 has vortec heads and the "ghetto grind" retainers)

or you will need to have the heads machined and use something like the howards 98212 springs.

 

305 Vortec heads work great on a 350 too, especially ones with a dished, stock piston. The oem 305 heads outflow the new mexico GMPP 062 vortec castings. I had a 305 respond really well to 1 3/4" primaries. 1.5" is for economy, not performamce. Dyno Dons headers, enough said. Alex spring set will drop right in place of the OEM springs and retainers and give you .550" lift capacity.

 

I put an Elgin E1136 in an Escalade and it runs really strong.

http://www.competitionproducts.com/E.../products/389/

 

Yes the 305 vortec heads will work on a 350, but I would NOT say they work great... The L30 305 and L31 350 vortec heads are in NO way alike.

The L30's has the same old bowl-ish chambers of the swirl port heads of the 80's with a bump in added at plug boss. http://www.crankshaftcoalition.com/w...BER_CN_059.jpg

The L31's has the true kidney shaped fast burn chamber.
http://www.crankshaftcoalition.com/w...eat_vortec.jpg

L30 is a 160cc intake port
L31 is a 170cc intake port

That 10cc makes alot of diff on bigger engines.. Gonna be hard to get 5500, 6000, 6500 rpm out of a 160cc port on a 350/355/360 cid engine.

L30 has a "swirl inducing vane in the intake port, next to valve guide.. Very much like the hated 350 swirl port truck heads of the late 80's.. Although the L30 head vane is smaller than the swirl port's vane.

L31 heads DO NOT have this vane.

L30 Vortec head flow
Lift (in.) Intake (CFM) Exhaust (CFM)
0.100 68 47
0.200 128 103
0.300 179 138
0.400 205 152
0.500 221 163

Flow rate of L31 Vortec heads

Lift (in.) Intake (CFM) Exhaust (CFM)
0.100 70 49
0.200 139 105
0.300 190 137
0.400 227 151
0.500 239 160
0.600 229 162

Again, yes the 305 vortec heads work on a 350, just like 10-15 years ago the 305 HO heads was the "trick ticket" for 350 engines, just like 30-40 years ago the 283 power pak, 327 double hump, etc heads was the hot head to use a 350...

Is it the best.. NO. Can you get a better head...YES Should you run a 305 head on a 350.. NO, not really, not unless that is your only option.

30, 40, 50 years ago there was not very many options for good heads for the street performance guys so you used what you could find that wasn't as bad as the normal stuff.

In today's market, theres no reason to do that, when you can get L31 vortec heads used for couple hundred bucks, that puts all of the 1950's-90's stock production sbc heads to shame. Or when you can get aftermarket alum heads that flows 240-260 cfm for $800-1200

 

The L30 heads I had cc'd 170cc out of the box and 56.5cc combustion chambers. With a little work they will flow 240-250 CFM with a 1.94/1.60" valve.

I wouldn't mess with the factory L31 heads in this day and age either, then again as cheap as a 350 block is, I would pickup a 350, but that is not what this post was about.

I have held these in my hands, bolted them on an engine and it ran its butt off! Compared to all the junk, cracked stock L31 castings with guides that are too tight and lift issues, these are a bargain.

http://www.jegs.com/i/ProMaxx-Perfor.../2151/10002/-1

 

Fast do you have a video of this running would love to hear it .....

 

I don't, but its a pretty mild cam. No lope and about 17-18 in/hg vacuum at 600ish rpm it idles at.