bhobbs

I built a 355 for my 70 Chevelle when I was younger with my dad making most of the decisions and was hoping to find out what kind of power it might be making. The car isn't running yet so I can't dyno it.

Anyways, here's the basics of the build.

Stock 350 .030 over
Flat top pistons
Smog heads milled to make 9.5:1 CR
Edelbrock RMP intake
Edelbrock 650 cfm 4 barrel
Comp 268H cam
Hedmen 1 3/4 LTH


The car was supposed to be done for me back in high school and a DD so my dad didn't want it to make too much power. I may end up changing the top end later on but I don't plan on it right now.

Paul Huryk

I'm going to say 275 to 300hp - you don't have the heads or cam to support much more than that level.

Notalent

Should see 290-300HP / 360-380TQ. I do a similar build with a 204/214 422/444 and it makes 275HP/360TQ with a stealth dual plane and 650 cfm carb.

bhobbs

What heads/cam should I look at to bump up the power but not loose street ability?

Notalent

how much power are you looking for? With a quick cam swap and your current parts you can see 325HP/370TQ.... 224/234 @50 .465/.488 112LSA....common cam....its made thru alot of vendors. That cam with a set of Dart 180cc SHP Heads should see about 380+HP / 415+tq.

bhobbs

Honestly, I don't know right now. Once I drive my car, I'll figure out if I want to go for more power or leave it as is.

I want to say as much as possible but I know I need this car to be reliable for me so I don't want to push it and have something fail chasing huge power.

Notalent

I would just swap the camshaft then for now....it will put you at that power level that most street guys want and cost you under $100 + some time. After that, you can always save up for the heads and still be reliable and have more power.

93 LT1 Vette

A lot of variables being thrown around here. I think a better vision of the end item by the Op is required. What car will it be in and what weight? What tranny behind the motor? What rearend gearing?

A big lumpy cam behind an auto with a stock stall and 3.08 gears will be a stone and a royal pain streetlight to streetlight. The current motor configuration sounds like a solid street build.

bhobbs

It was an auto but I swapped in a M22. The rear gears are currently 2.73:1 but I want to swap in 3.73 with a limited slip.

Car is a 70 Chevelle. Not sure on weight but should be close to stock. Only major changes are 4 wheel disc brakes and different wheels and tires.

93 LT1 Vette

I'd finish the 3.73 posi (12 bolt I assume) first and run the current engine setup exactly the way it is, with the rockcrusher and a good street clutch.

AFR 195's with a strong roller cam in the .550 to .585 neighborhood would make for a nasty 355.

The cheap way would be, Vortec heads, high lift valve springs,roller rockers and a Voodoo series cam package

Ad. duration 268/276
.050 duration 228/232
Lift .489"/.504"
LSA 110
Power range 1800-6200

bhobbs

It's a 10 bolt but if I can find one in my area, I will pick up a used 12 bolt and rebuild it or buy a Moser.

I was looking at AFR heads and a roller cam earlier.

Notalent

AFR's are nice, but the Dart SHP180cc will save you ALOT of $ and run the same ;-) These have the Platinum series work done to them.

The cam I mentioned is very streetable and not lumpy at all. It will work nicely with a stock stall if need be and street gears. I build/sell over 200 of them a year....and had a similar version in my Chevelle before I went to the 496ci...a great street warrior package thats daily driveable and still produces vacuum for power brakes.

BTW your car should be 3800-4000lbs.

bhobbs

Would the extra flow of the AFR 1040s be worth it over the Dart 180 SHPs for a 355 if I go with a bigger roller cam?

93 LT1 Vette

I'm just giving you options. Your DAD built a very streetable and solid base in the 355. The AFR's will give you the same base when and if you want a 383, 406 or even a 420+ cube motor. Face it, even a strong 355 4 speed 3.73 setup will have trouble pushing a 4000 pound Chevelle to dragstrip or street racing fame, ask Notalent I'm sure that why he's packing a 496 BBC on the street.

A 12 bolt and M22 will survive well behind a large cube small block or a Big block for that matter but it's only a matter of time before your looking for more power no matter what heads and cam you run in the 355.

Plan ahead and save your cash and build the motor you really want. Drive the Chevelle with the 355 as is, enjoy the up coming summer and remember "There is no replacement for displacement" especially when your moving 4000 pounds from the dig.

bhobbs

I have never ran the 1/4 mile before and I have wanted to try but it's not like I'm trying to set records or anything.

wesmigletz

iTrader: (6)

The 268 Comp is a nice street cam. With your rear gear upgrade, you should have no trouble running a low-mid 14 with your Chevelle. It sounds like you're still learning. You have a good, solid, reliable combo getting it running and learn on it before you start throwing money after parts.

The cam referenced by NoTalent is a nice cam, and I've run the Summit version of it (Sum-1105), but I don't see you gaining much over your comp cam.

moge11

Ive run it too... And with todays Cam grinds available, THAT CAM is a waste of money when trying to get More Power.... That cam is ONLY a good choice in the type of build that the OP already has completed...

Like you said, it would be hard pressed to even pick up over what he already has

stevo1988

I dont mean to hijack this thread but i have a similar motor and i was wondering too what kind of power i am making.

its a 355 aswell with flat top pistons making around 9.25:1 CR
world s/r torquer 67cc chamber heads with 2.02/1.60 valves
comp 268h high energy flat tappet cam
1.6 ratio full roller rockers
dual plane aluminum high rise intake
everything is ported to match gaskets
edelbrock 600cfm carb
hooker 1-5/8" to 3" headers

I chose this cam at first to accomodate a 2000-2300 stall converter, th350 and stock 2.41 gears out back. It has excellent power off idle and lots of torque so the car moves well.

I plan to swap the 2.41 to anywhere between 3.08 to 3.73, if so what would be a good cam to switch to (i am willing to retro-fit a roller cam too) I know the heads i got might be the limiting factor but there has to be something that could give me a boost in horsepower. (carb will change too)

moge11

swap your stall to a 3500 and use a 3.23 gear.... then use a 224/230 or 230/236 roller such as the xtreme energy grinds from comp.

SSellers

Curb weight on a '70 Chevelle is 3400 lbs with fluids. I had a similar 355 that made 263hp/310tq at the wheels. It won't be a record breaker but will be a fun ride with a 3.42 or 3.55 gear and peak torque down in the 3500 RPM range. 3.73 gets old at 70mph and above on the highway. An M22 has too high of a first gear (2.20) to run anything under a 3.42 at the bare minimum and be able to move out in first.