Spike_Akers

I'm finally ready to put a motor in my 84 z28. Im planning on the following combo.

Stock bore 350 with 4 valve relief pistons,
Stock vortec heads from a 98 truck
Dual plane summit intake
Summit street strip 600 cfm carb
Voodoo cam adv. Duration 256/262
Lift .454/.468 lsa 112
Compression should be roughly 9.6:1
Car has 3.73 gears and 700r4 tranny for the time being.

Anyone have a rough estimate what kind of power this would produce?? And on a side not has anyone used the summit street/strip carb??

DeltaElite121

which cam is that... just post the cam part number so we can see the cam card specs.

What exactly are you trying to do with this setup so we also know which direction to send you. I see MILD, but that doesn't tell me much. What are your plans?

Spike_Akers

http://www.lunatipower.com/Product.aspx?id=1982&gid=287 there's a link to lunati.
The goal for the motor is to be daily driven with some power, hoping to touch 300hp maybe hit 13s in the 1/4 mile... Nothing that can't get me back and forth to work reliably and still be fun to drive

cuisinartvette

Youll like that cam will do what you want it to.
Dont see why you couldnt touch 300 or so with that.

DeltaElite121

Spike, I have a brand new XE274 I can sell you if you're interested. I had it for my new motor and yanked it before running it on the street for a solid flat tappet. I have no use for it, and it's a new cam so maybe you could use it more than I can. Originally, my motor started out real close to yours, actually. Things have changed since then, though.. thus why I don't need it.

86LG4Bird

iTrader: (1)

"Stock bore 350 with 4 valve relief pistons"
I read that as flat top pistons; however to come up with a 9.6 CR, you'd have to use a thick head gasket, which I think is a mistake. It would make the motor more detonation prone.
I'm assuming it's a stock bottom end, which typically has a deck clearance of .020 to .025
I'd run a .015" shim gasket in that motor and step up a size on the cam.

Spike_Akers

I'm just alittle afraid of 10:1 on pump gas... I understand that a tight quench would decrease detonation, but would it be safe on pump gas?? And I would need to run a bigger cam with that as well... What about dished postons?? That would lower my CR... Any input on the carb?? Would 600 cfm be enough?? I can't see needing 750... But I'm not incredibly knowledgeable on choosing a carb...

Orr89RocZ

iTrader: (20)

Would like a bigger cam for that higher compression. My friend ran very similar combo using a stock LT1 cam from a fbody and ran 13.5's in his 83 chevy pickup truck! Would go 12's in a thirdgen. His ran best with a 750 double pumper but i dont see why a 600-650 cant work. I just dont know much about carbs. I like efi. If thats a roller motor try to find a takeout zz3-zz4 cam or a lt1 cam could work but id like to see tighter lsa. Cam you chose is good but abit small. Id step up a tad especially with that compression

DeltaElite121

I vote for a 750. If anything, you can downjet it if necessary. Can't "grow" with a small carb, though. If you're going to go real mild, look at Lunati's "268" grind. Harold did grinds for Comp and Lunati, and Lunati currently has his most recent grinds (the VooDoo series). It's better to have a little too much and to reduce the carb, than it is to not have enough and end up suffocating your potential until you drop another $500 on a decent carb.

Look at the Proform 750's with annular boosters. I don't see the point in buying a new carb without the annulars, honestly. Used? Debatable. New? Do it once, and do it right.

86LG4Bird

iTrader: (1)

Please confirm whether you have flattop pistons with ONLY valve reliefs (that would be about 5 cc's total), or..
whether you have stock Vortec-style dished pistons with valve reliefs (which would be about 11 cc total).
A lot of guessing going on here right now.

unknown_host

iTrader: (1)

With your goals, I would copy the 350HO crate engine, 330hp and 380 ft lbs. I had one in my 82 Camaro, it ran consistent low 13's at 106. This is the camshaft that comes in that motor, and is very similar to the Lunati you have listed:

http://www.summitracing.com/parts/nal-24502476

Spike_Akers

Gen I flat top with 4 valve reliefs... The heads were brand new freebies from a salesman at work not having the truck looked at before selling it, put 2 new heads on it, then it threw a rod 300 miles down the road so I don't wanna spend money on these to get higher lift than .470.. the block is out of an 86 k20... That was free as well.... Thus the interest in keeping it as close to stock as possible. But if I need to ill spend money where I need it...

edit: i just went and recalculated my CR... and with a .042 head gasket that puts me at 9.75... is .042 really thick enough to cause problems? because i feel (may be wrong) that this is an average gasket thickness...or i could go with say these http://www.summitracing.com/parts/sl...make/chevrolet and a gasket of 0.026 and get 9.58... im not too keen on using the copper gaskets on a daily driver... have heard they are kind of a pain...

aldrichg9

I know I'm new around here but I'm running 11:1 in my cast iron 6.2 and use only pump gas. 93 octane of course but 10:1 is certainly nothing to be afraid of.

Spike_Akers

That's computer controlled right?? The 6.2s have ignition mapping that greatly reduces detonation if I remember correctly. Some of gms stock motors have 10.7 - 11:1 that run on 87... Ignition mapping is a powerful thing.. carbed engines don't have that luxury... And pump gas is scary in its self because even though the pump says 93, you may (and in certain areas definitely) be getting much lower octane.. and since I'm planning on this being a dd I want to be able to run 87... And 7.9:1 dynamic compression should be fine on that... Hence wanting to keep the lower CR... I've never planned out a build though so I'm not sure if these components would get me what I was aiming for... Outside of the guys saying go bigger sounds like it should work... Would like to hear thoughts on the dished pistons vs the thicker gasket though

86LG4Bird

iTrader: (1)

You have the perfect opportunity here to build a great running engine. Dished pistons would definitely be a move in the wrong direction.
Leave the short block alone. Spend the money on a set of valvesprings and retainers (you're going to need more than the stock Vortec springs for anything beyond the stock cam anyway) to give you the clearance to run a better cam. You haven't already bought the cam, have you?
Run a .015" shim gasket, the quench will be great, you'll have about 10.2 SCR.
Pick a cam with better lift and about a 268 advertised intake duration, and you'll be about 8.4 DCR. (stock Vortecs in trucks run 8.1X DCR with worse quench, 195 deg tstat, and margin for towing, etc.) With the Vortec chambers and the better than stock quench, you'll get great mixture motion, less timing required up the whole curve to make the power.
Figure on only about 30 degrees max timing.

Orr89RocZ

iTrader: (20)

^ agreed. 268 cam is mild in a 350, but a 12 sec combo

cuisinartvette

your 600 should be fine
rather jet up a smaller one than lean out a bigger one it will be more snappy and responsive. Opinions will vary