Vortec355

Well the season is now over and the I can't seem to go any faster with the big cam I put in my car earlier this year. I guess the vortec heads were maxed out with the previous cam 488/502 224/230@.050 112 Centerlobe. The cam I put in this year 562/571 248/258@.050 112 Centerlobe didn't do anything but make the car slower. I did put a bigger stall in it (4200), but it has no topend still. It might be the dual plane killing topend, so I decided to go back to the drawing board. I would like to go with a 540, but I'm looking at 10K in the hole. Anyway I pick up a set of new Bowtie Vortec 215 heads. They are like the fastburn but bigger 84cc exaust ports. I'm going to run the same 355, but put forged pistons and maybe rods. I have a forged 5140 crank and stock powder rods with 2000ARP pro series bolts. I want to go with a solid cam, but not sure how big. The specs for the cam are 675/635 264/272@.050 108 Centerlobe. It's an Isky. The other is 670/620 260/264@.050 108 Centerlobe. It's a Howards Cam and was used in Super Chevy on a motor that made 650 horses. What would be the best cam for a 355 in a 3800lb car with 4:56's and 700R4 with a 4200 stall, and 850 carb with 12:1 compression.

thebowtieislife

a couple of things i see that you could try is ditching the dual plane intake opt for a victor or a nice bowtie single and 1" or 2" carb spacer (plenum volume) that will help top end but how hard do you plan on turning the motor? the 215 heads will really help you out. what size tire you have? those 4:56s are pretty deep (not good for trap speed) with the set up you have 3:73 to 4:10 would work better. id stick with the 2nd cam you tried the 562/571 248/258 112CL with the head, intake, change. just an idea on all this, never said how much power you want or how fast the car is, or how fast you wanted to go

Vortec355

500 rwhp at least if not more, I have a 4200 stall , 4:56's with a 28 inch tire so I want to spin it to 7500 RPM's tops. The car runs 8.0 @ 86.5 with a 1.79 60ft in the 1/8th. Last year it went 7.85 @ 86.3 with a 1.65 60ft. I'm running a 700R4 tranny fully built. I was told the cam should have been on a 108 rather than a 112. It revs slow as it did with the other cam. Is it the manifold causing the motor to rev slow, or is it the cam being on a 112? I have to pull the motor out to change the cam and manifold and I want to do this nice, not twice or three times.

thebowtieislife

the intake could be making it rev slow but i doubt it, although a single plane would work better on your set up. i think the 850 my be a bit to big too, i've seen that on carb set ups a little rule of thumb for a small block is about 100 cfm of carb to every 1000 rpm to the motor (give or take a little) but i think a 700 to 750 cfm would be the better carb, plus the smaller carb will bring back some throttle response, some bottom and mid range tourqe. going to a 112 to a 108 CL on the cam may or may not change anything (to many factors in cam profiles) but like i said about the one cam you had i think you'll have better luck with it, i think the main problem is some parts that arent working well with others

Vortec355

The heads and intake are holding me back def no question. I want to build a big block, but in the mean time I think I will stick with the cam and change the heads and intake, maybe put some rods and forged pistons with a 250 shot. I'd rather put money towards a 540, but I want to be somewhat fast for now. Most small blocks that are running low 9's and 8's are all running big shots.