I have a 350 that will be going in my 83 Z28, It will have an edelbrock intake, 650 carb, hooker headers, flowmaster exhaust. I will be camming it soon, I am looking at the lunati voodoo cam and lifter kit. does anybody think this is a wise choice or go with a dif. cam? How much power should I be able to get out of this set up? any info is appreciated!!
Thanks, Brody

 

What heads? Which Edelbrock intake? Which Voodoo cam?

 

stock 350 heads off a goodwrench motor, pretty sure its a performer intake that i'm buying since its a throttle body/carb conversion, and this is the cam and lifter kit...
http://store.summitracing.com/partde...rt=LUN-60102LK

 

The cam is okay, but would work better with a Performer RPM intake manifold.

Goodwrench 350 heads are large chamber, poor-flowing port truck heads. You'll be right on the ragged edge of lift capability with the VooDoo cam, but you can be sure the springs aren't up to the task. If funds allow, seriously consider a head change. sdparts.com has some good Vortec head kits with intake manifold, they have one with upgraded heads that can handle more lift, the Vortec RPM intake manifold, gaskets, rocker arms, bolts - everything needed to put the heads on a SBC for about $1100 (plus shipping).

Depending upon what you plan on doing with the car, a little more cam with that head/intake kit would make a beast out of the engine.

 

When u say on the edge of lift capability are u saying that the valves will be close to the piston? the kit comes with new springs so that will be ok right? Yea if I had the money i would def buy some new heads but as of now I can't.

 

By lift capability I mean the distance between the top of the valve guide and the bottom of the retainer at full lift. Tends to bend things.

 

will I be ok with buying this cam? I will be buying the springs too, will this help at all?

 

Springs are a must, but that won't help with the guide-to-retainer clearance problem, or the fact that the heads are lo-po wonders.

 

well what is the worst that could happen by running a slightly too large cam, will it spin a rocker and blow the motor or just end up running shitty? I read an article from high performance chevy about basically the same build, except a comp cam with .477 intake lift and .480 exhaust lift, on a goodwrench motor with stock heads and it didn't hurt anything, but then again they probably didn't run it for very long...

 

Heads are going to be your biggest improvement. Get a set of Performer RPM heads. I ran them for a LONG LONG time. Several different engines.
89 Camaro 355 with RPM Intake,750vacc. carb,Similar cam as your running with the RPM Heads.. 350th trans with 2500stall, 3:89 gear.
First pass at the track was 12.40@113mph. Pump gas... of course.
That was 14yrs ago... Run TRW Forged flat tops.
YOu should get the same results with a good tune.
If you use the truck heads you'll be disappointed in it's performance.
When your Nat. asperated you gota have the flow!
RPM heads are under 1000.00 now assembled ready to run. Springs are good to .575lift (non roller)
Good luck,
Scott~

 

Ummm, you'll bend things, like pushrods. Bending things inside an engine is typically not a good thing.

 

should I get new high perf pushrods from lk comp cams?

 

You normaly use hardend push rods on guidplates. You can get them now if you choose. They can only help now/later.

I still strongly urge you to go with the RPM heads... even if you get them used from Racingjunk.com or e-bay. They are a great head for your setup.

Your not going to get any results with the heads you've got. Putting any money into those heads is a poor investment on return.

Regular Performer RPM intake... Your cam and have some fun.
I've been down the same road your on... Those stock heads are going to choke the engine down badly.
~Scott

 

yea I agree... as soon as I get enough money I will def. buy a set of heads... were you running slicks on your 89? thats a good time though, I would be very happy with that being that I am 17 and its a daily driver. Do you remember what kind of gas mileage it got?

 

Look, you need to verify that you have at least .060" more valve travel than lift, primarily on your exhaust valves since the cam has more exhaust lift than the intakes do.

Typical max lift on unmodified stock heads is around 0.480". Some can handle more, many can't handle that much. You verify this by removing the valve spring (you have to hold the valve closed while you do this - either by air pressure, putting the piston up to TDC, or stuffing rope into the cylinder through the spark plug hole), put the retainer and keepers back on, and measure the difference between fully closed and fully open (removing whatever you did to keep the valve closed, of course) - you need to do this with precision measuring equipment - Mom's yardstick ain't gonna cut it. You need to do this on each and every valve.

Until you know you can handle that much lift, it doesn't make any difference whatever else you try to do. When things hit, something will bend. You don't want things to hit, and you do want at least 0.060" cushion travel over lift.

 

Back then gas was under 2.00/gal. for 93oct.! I'd guess depending on your driving habits you'd get 13-16 in town and if you've got overdrive 18 on the highway. (carb and tuning required)
After my 355 engine I put together a 406sbc same heads same cam went 11.60's on motor and 10.50's on 150hp No2. @132mph.
Any camshaft with under .500lift won't be hitting the pistons unless you've got your timing chain on wrong Lol... Once you get into the mid .500's in lift with a true flat top piston is where valve clearance might become a issue.
~Scott

 

One more time, valve-to-piston clearance isn't the issue. I know they talk about that all the time in magazine engine build articles, but as you said, that's rarely a problem with a mild build.

Valve guide to valve spring retainer clearance is the issue when the lift at the valve gets over about .48". That is the case with the originator's cam, and the replacement engine heads are famous for having problems when you try to do anything more than a lame cam with them.

 

Found these on E-bay: Click here: eBay Motors: PROCOMP SBC CHEVY 350 383 190CC ALUMINUM CYLINDER HEADS (item 270192406119 end time Dec-09-07 07:53:2
I don't care for the CC in the chamber but if your using the stock pistons you'd be ok on compression. I'd CC it to be sure. You can run up to 10.9-1 Compression on 92oct. no problems. For 600.00 you'd have almost that in putting guides,positive locking valve seals,valve job ect into a stock cast head that's got miles on it.
Just a thought..
Hope that helps, Scott~

 

hmm, it wouldnt let me click the link... but I tried to find them and I couldn't find any for 600 that were assembled, were these ones bare? Could this test be done with the heads off the motor? I will be taking them off to replace the head gaskets anyway and unless I am missing something it sounds like you can do it with the heads off. I have access to precision equipment so that won't be a problem.
Thanks, Brody

 

no you cant check compression with the heads off......

 

Go to e-bay and enter Pro Comp Head That'll pull up all the pro comp heads. Not sure why that link didn't work. They are 695.00 for the pair assembled with springs good to .600 lift.
You can look up your stock engine spec's and come close to determing what your final compression ratio is with a different cc Chamber.
Most GM engines have slightly dished pistons with 4 valve reliefs in them which yealds 9.5 compression. With a tighter chamber you'd be increasing the compression. We just need to determine how much. Allum. heads are more forgiving on compression than iron. I ran 10.7-1 compression on mine with no problems.
If I had the stock compression ratio and the stock CC of the head chamber I could calculate the compression for you. See if you can find that info for me.
~Scott

 

I'm not checking the compression with the heads off, I am checking maximum lift on the stock heads... ok I will try to find that info out, thanks a lot.
Brody

 

best question EVER

 

ok so I found out that this 350 has around 8.0-1 compression and a 76cc combustion chamber.
Brody

 

Uh, yeah, what's new? Been trying to tell you that.

 

yea I know, I never thought that they were good, but that other guy said he would figure out the compression of the engine with a dif cc head on it so go easy alright? I'm not trying to go against anything you say or anybody else.

 

dude.....dont mess with truck heads.....low compresion...low flow......if you cant afford a decent set of 350 heads....get some 416 305 heads.....at least they make good compression

 

I did a real quick calculation: Compression Rato=

720.74072(Cylvol) + 95 (Chamber/gasket) volu.
Devide by Chamber/gasket vol 95 = 8.5-1 comp.

If you take the chamber/gasket vol down 10 to 85 with the same calulation
you'll end up at around 9.5-1 by putting the heads on.
Your safty zone for pump gas is 10.7-1.
I think you'll be safe to install the heads with the tighter chambers if you gave me a accurate compression ratio.
Hope that helps,
Scott~
(I rounded numbers just to make it simple)

 

yea, i dont have the money right now for a set of heads, i do have the heads off of my 305 H.O. but the motor threw a rod, the heads look fine but they also leak tested bad a while ago. As soon as I get the money I will be buying a set of heads, but i'm not really sure what the sollution is right now. Thanks for the help UR50SLO.

 

The 416 heads off your 305 are a good addon. If you have access to a die grinder you can do a bit of port work and have a set of decent heads for cheap (almost free).
Drop by a machine shop and ask them if the heads will leak. They'll set a straight edge over it and slip a feeler gauge through a few spots. You *may* have to slip the guy $10 for his time. That'll give you a yes or no. If they are warped, decking the heads until flat probably will cost $60-$100 (max!). I'd do it. In fact, I did, see sig.

 

When I had it leak tested, they said it leaked through the top and bottom end... when it leaked through the top was it leaking out through the head gasket or through the valves? All I did was look at the heads and I didn't see any gashes or cracks, but one piston was ate up really bad, should I be worried about the head being hurt?

 

You proaby won't see where they are leaking unless you pull the valves out and see what the seats look like. They would have to back off the rocker arms to do a leak down test. If they did it with the rockers on the test was worthess. Doubt it was leaking from the head gasket. SBC's are not known to have issues there.
If you end up using 305 heads on the 350 make sure you open up the chamber to unshroud the valves for the larger bore. It's a budet small chamber head but nothing can replace a good aftermarket allum. head.

What happend to the piston? (are we talking about the 350 or 305 now?)
~Scott

 

yea, i'm not sure how they did it, do you mean porting them when you say open up the chamber? yea i'm gonna def. be buying some nice heads as soon as i get the money, i'm selling a 700r4 so maybe the money from that. The 305 threw a rod and sent it through the oil pan and after i took the head off i saw how screwed up the piston was. it actually cracked the block too.