Maybe an engine guy can help me out here. I'm rebuilding a 350 with new pistons, cam, lifters, bearings (keeping the OEM crank). For a pure stock class (maybe 5500 rpm) what do I need to balance in this engine? Some people think having the whole rotating assy balanced is overkill. What do you think? Thanks

what BRAND OF PISTONS ARE YOu USING?

iF YOU CAN, GET SOME POWERED METAL RODS FROM A STOCK 350 truck or LT, they are stronger.

If you are using the better pistons and PM rods, and because your only turning 5,550 rpm, you may not need to balance the engine.

get a good oval track oil pan

Do not use to big of an oil pump.

See competition products for really cheap prices

competition products,,,cheapest engine parts


http://www.competitionproducts.com


PIC of PM rod

http://www.competitionproducts.com/prodinf...?number=350LT5A

cam
http://www.competitionproducts.com/prodinfo.asp?number=E860S


cam and kit
http://www.competitionproducts.com/prodinf...p?number=E860SK

Cam Craft specilizes in Low Lift rules Oval track cams,

Tell them you have a low lift rule AND a vacuum rule

this means you wil have to use WIDE 114 to 118 lobe centers and advance the cam timing.

http://www.camcraftcams.com/Archives/monthlynews0403.htm

Thank you!

all this for $130 for the cam and kit

Elgin Hydraulic Flat Tappet Cam Kit
Complete kits include:
♦ Set of matching performance hydraulic lifters
♦ Set of matching performance valve springs
♦ Set of heat-treated steel valve locks
♦ Set of high grade umbrella valve seals
♦ Assembly lube oil




Elgin, Hyd. Flat Tappet Cam, Chev SB, .404/.414, 114 LC
Chev SB
Lift: .404/.414
Duration: 269/271
Duration @ .050": 202/207
Lobe Separation: 114 LC
Smooth idle, Low rpm torque


=======================

Camcraft

http://www.camcraftcams.com/Archives/monthlynews0403.htm

Important technical info for lift rule classes.

We have had some problems with customers not being able to get enough rpms from low lift profiles. This is usually due to not checking open spring pressure. The spring specs may state a sufficient pressure but it is usually for a higher valve lift. Be sure to check your actual installed spring pressure at both open and closed checking heights ON YOUR HEAD. The open pressure is the most important. On low lift applications it may be necessary to shim the springs to 20 or 30 lbs over the recommended seat pressure to get the right open pressure. Failure to do this may result in valve float and engine damage.

Below is a current list of .390/.410 SBC profiles.

HLLM Series; A low lift hydraulic race series based on our HMT series. A little more radical and only a little harder on valve springs. Proper maintenance is important. These have a much shorter .004 duration than older HLL series

Duration Cam Lift Valve Lift
.004 .050 .200 1.5 1.6 1.7
269 226 137 .274 .410 .438 .465
273 230 141 .260 .390 .416 .465
273 230 141 .274 .410 .438 .465
276 234 145 .260 .390 .416 .442
276 234 145 .274 .410 .438 .465
282 238 149 . 274 .410 .438 .465



I am just GUESSSING that i would pick the first profile for the intake and the exhaust lobes but because you HAVE to use a single SMALL exhaust pipe, NO duals allowed. IMHO, I DO NOT like more duration on the exhaust when using Stock cast iron exh. manifolds. I like the intake and exh. duration to be the same.

Next i would guess that you would want a wide 114 to 118 lobe center so that you would have good vacuum per your rules and also and advance the cam timing to get more low end power.

.004 .050 .200 1.5 1.6 1.7
269 226 137 .274 .410

the above with a 114 to 118 LC
\
the above has about 24 degrees more duration a .050 lift when compared to the Elgine cam. yet the duration at .004 is about the same.


Tell the folks at Cam Craft all your engine rules and car weight and tire rules,,,Cast iron exhaust manifolds only, SIngle exhaust only, Vacuum rule, 9.5 compresson ratio rule, stock heads,,,,

tell them about your track.

They then can tell you the best cam to use.

Arnold.

I have used ISKY cams for years, and they will custom grind you a cam.

I would guess youwould want a cam with about .410 lift on the intake and exhaust, with a duration of 220 to 222 degrees @ .050 lift on the intake and the exhaust, with a 114 to 118 lobe center to get your good vacuum. also advance the cam alot.

the below cams would work if they had 114 to 118 lobe centers, but they come with 108 lobe centers and have poor vacuum and idle.


http://www.iskycams.com/timingchart.php?pr...t_number=201SL1

http://www.iskycams.com/timingchart.php?pr...t_number=201LR1

http://www.iskycams.com/

What do you guys think about this?

Building a smaller lead sled V8 to get the weight break,,,

Use the mid 1990's Impala 5.7 V8 block and pistons ( 4 inch bore, flat tops)

Install the 4.3 V8 mid 1990's Impala crank ( 3 inch stroke) and Rods (5.94 '' long vs. 5.7 '')

Install the 4.3 V8 mid 1990's Impala heads ( thye have smaller chambers than a 5.7 Liter)

Install the LT-1 Roller cam and lifters

This combo would be,,,

302 CI,

4 inch bore, flat top pistions, high compression,

3 inch stroke,

Longer 4.3 V8 rods ( 5.94 ")

what do you think?

crower cams vacuum and lift rule cam

http://www.crower.com/misc/m_cat.shtml

http://www.crower.com/

VA CUUM RULE - Perf Level 5
Lighter car, 3⁄8 mile track, low end
Redline: 6500 rpm plus

Grind # 238H242

116 degree lobe centers

Advertised
Duration
Intake Exhaust

300° 300°

Duration
@ .050"
Intake Exhaust

238° 242°


Gross Lift
1.5 / 1.5
Intake Exhaust

.390" .410"

thats one beast of a motor for a lead sled trick!

it's also illegal, by the way mr. trick they did away with the vacuum rule so there is no need to get a vacuum rule cam.

in my opinion if you are rebuilding it with stock replacement parts it would be probably ok, concidering most of the engines gm built, the balanceng was only close, not perfect to start with. It is never a bad thing to have the rotating assembly balanced, but if money is a issue it will be fine, i can assure you that there is quite a few running around a/c that are straight out of the junkyard so either way you will be one up

Btw, closer to 6000rpm is very common in the lead sleds

Yeah if you plan on running a 350 turbo you will run right around 6g with a 273, and down around 53-5500 with a 256.

What do you prefer, the 273 or the 256?

from my experimenting, ive been happiest with the 2.73 over any other gear and a 350 turbo in first gear.

Ill tell you in a couple weeks! lol

find a 2.92 gear. do the math hehehe