bottlefedbaby

I'm in the process of building a 355 with 062 heads on a one piece rear main seal block probably a simple edelbrock intake and a 750 carb, I got silvolite pistons and stock older style rods, now I like the sound of the 268 but its going in a truck that will be drove often and I don't plan to turn more than 6000. Any suggestions wont go unheard!

1994Z28Lt1

iTrader: (1)

a 750 carb is far too large for either of those cams with a dual plenum intake manifold, stockish vortec heads in a pickup, go with a 600 or 650 you will have much better response, off-idle torque, and fuel mileage, revving under 6000.

with a 750 and vacuum secondaries you'll hardly ever get into the secondaries with that motor, with mechanical secondaries you'll probably bog

bottlefedbaby

Im positive I want a carb bigger than a 650... I put a 650 double pumper on the stock 350 and sold it and just had the stock quadrajet rebuilt.

1994Z28Lt1

iTrader: (1)

Go ahead and do as you please, but gaining 3 hp at 6000 rpm at the expense of low end power and response (which is what you want and need in a daily driver pickup) go right ahead.

sounds like you got your mind made up anyway.

FYI I put down over 400 RWHP with a throttle body that flows about 600 CFM

I also built a vortec headed 355 with similar sized cam, shorty headers, edelbrock dual plane intake, in front of a T5 in a 86 mazda RX7, I had a edelbrock performer 600 CFM carb, the secondaries didn't even open until over 4000 rpm, that engine had plenty of carb on it

bottlefedbaby

If I would have had better luck with the first 650 I'd definitely go that route this time but the quadrajet managed to be better all around. I haven't made up my mind yet.. and 750 might be a little larger but I do believe I can play with it enough to get what I want. If I dont get that with a 750 then my next choice would be the 670. And I wouldn't call it a daily driver its gonna be more like a toy. Any suggestions on the cam? Thats where im pretty confused, I like the rough idle of the 268 but I am aiming for decent power here.

bottlefedbaby

Bump..

Z28 6spd

iTrader: (3)

The 268 cam will be plenty for what you're doing. A larger cam will only take bottom end power away. I would also vote for the 650 carb on this application.

bottlefedbaby

I really wish I could find a 700... I feel like that would be better.

1997bird

iTrader: (2)

Lunati Voodoo # 60102

262/268 seat to seat
219/227 @.050
.468"/.489" lift with 1.5 rockers
112 LSA (I would have them grind it @108 LSA)
108 ICL (I would have them grind it @104 ICL

I would look at Quickfuel Street Series 750, as part time throttle response would be easier to tune. The 650 would have a lot of velocity behind the fuel charge and can give a person fits tuning the partial throttle cruising down the road.

bottlefedbaby

How does that cam sound? Is that a vacuum secondary carb? I figure with a 108 lsa it should lope a bit lol the truck wont be a daily driver more like a toy to beat on. A plan to run about a 2000 stall with the th-350

1997bird

iTrader: (2)

You can get it with a mechanical secondary or a vacuum secondary. It would have a little chop to it but nothing radical, the vacuum brakes would still operate just fine. I would use a 2500 stall or depending on the transmission used a GM convertor that would stall about the same.

bottlefedbaby

I think I'll look at the vacuum secondaries, any idea what kinda numbers this motor will make? Im shooting for maybe a tick over 10 to 1 I can get 110 at a gas station I few towns over.

1997bird

iTrader: (2)

Has this engine been zero decked? Have the heads been machined with a different valve job than what GM offers? Were you going to use the Performer or Performer RPM intake? I would be sure to use the correct valve springs to match the cam used (make sure that the springs are installed with coil bind & retainer to guide taken into aaccount). I would shoot for 9.5:1 compression due to the factory combustion chamber design & how it works uunmodified from GM.

bottlefedbaby

The block has decked to 9 inches and the heads haven't been touched o th other than rolled pins. The way its all laid out I should have a 10.26:1 compression.

1997bird

iTrader: (2)

I could be wrong, but I think that at your compression your going to be on the verge of problems running on 93 octane. Your not going to be able to give the engine as much timing as you could have with a little less compression. I would say your build going to end up around 415 HP.

ATK Engines

iTrader: (1)

Post up the cam specs.

bottlefedbaby

I plan to keep the fuel with aces so im confident I wont have any problems, as far as the cam goes.. I'm leaning to the xe 268. But that's up in the air still. I want I bit of chop to it but again I don't plan to turn past 6000 rpms. And im not a thumper fan.

bottlefedbaby

I'm close to just selling everything I got now and buying a 5.3 or a 6.0...