so my car will not rap past 4500. it seems like it has no power. and it will rap untill 4500rpm where it seems to stop or cut out... any idea

sbc350-t5 as far as i know the motor is a crate350 350hp/400tq

i got the timing around 13/14 before with the vac unpluged and the hei has the timing advanced kit with the second set of sliver springs and weights.

i put a vac gauge on to see if the valves were loose. the gauge is solid on the line 18 between late ing timing and normal

could it be my pick up or coil in the distributer. or my valves to tight....

 

If it's a crate motor, the valve adjustment was fine when it came out of the crate. Did you play with the valve adjustment? If not, move on. Are you running a stock 305 exhaust system? If so, there's your problem, guaranteed.
Here's one example of why I dare say that. I have others. Anyway, I had a fully built L69, COMP cam, ported heads, Edelbrock intake, et cetera, with headers, matching Y-pipe, a test pipe in place of the cat, and a DynoMax 2.5" cat back. In gear, I could feel it was dying at 5000, but in neutral it would zing to 5500. I replaced that muffler with a Hooker Maximum Flow 2.5" and suddenly it was pulling hard to 5500, and would go 6000 in neutral. I should've then tried stepping up to 3", but I traded the car to a friend in need.

 

BTW, 18" of idle vacuum is very good for that cam.

 

i have the comp series hedderman headders with ypipe full 3"straight back to a flowmaster. also a edelbrock peformer intake with a holley 650dp

 

Go double check your Y-pipe. Every Hedman Y I've ever seen was 2" into 2.5", and if that's what you have, then that IS the problem.

 

its 2.5 straight back or 3". ive never had this problem before. the last motor was a 650hp sbc and it never did it. same exhaust system.

 

Did it just start doing this? It sounds like a carb issue to me, I would try larger jets in your secondaries.

 

Well, with exhaust ruled out, are you sure your secondaries are opening right?

 

what heads are you using?? what cam?? what is your total timing at (not initial)?? if you have a dist. spring kit in there, you may have too much total timing at top end....too much advance.

 

the carb seems to be working good. everything works on it.

as far as i know the head castings are: 93417369
and cam is 222/222 450/460lift thats what i was told could be diffrent.

should i go down a spring size on the distributer?

 

i could pull it and see but its getting a lot of fuel!

 

there are 3 possible engines it could be. Specs for all 3 of them can be found on the GMPP website. I think he's running the 88958602. It's Vortec heads with a HF cam of 212/222 at 0.050", 112.5 lobe sep, 109 ICL ( 3.5 advanced )
with 0.435 / 0.460". The thing should be pulling hard past 5500.
Too much timing is possible. Vortec heads hate more than 34 degrees total. they nearly always do better at 32.

 

Holleys tend to go fat at the top end, and this can noticeably hurt top end power

 

i used the middle spring set

 

the heads are not vortec they are the old style heads not center bolts

 

I thought that if the jetting was rich it would stumble not choke. If I am correct in saying this than he needs larger jets. I would step up 2 sizes at a time until you get a stumble then back of 1 jet size.

 

could be running out of air in the heads.....
run the car about 3k with the vacuum adv. unplugged, time it, see what it is at. you'll need an adjustable timing light or a timing tape on your balancer to read 30+ deg. I agree with the about 32 deg. total.
if you don't have that stuff.....try turning you initial timing back say four deg. or so...if you running 13-14, try 9-10...see if that makes any difference, if it does then that's it, if not, it is something else. carb issue, head flow problem, etc. etc. the cam seems big enough.

 

Yeah, I'd run the black springs, and start with 12 degrees of initial. Those heads are still good enough to pull hard to 5500 with that cam. But if you have the 929 cam then you are running out of air. I'd pull the cover, put a dial indicator on there, and check the intake lift. If your intake valve lift is less than 0.390", then it's the 929 cam.

 

when i mash it car gets deep and pulls but it seems like there should be more power!. and once the car hits 4500 it stops pulling and the motor seens just to stop reving

 

I just edited my last post, please re-read.

 

that was my thought too, not enough air flow if timing is not the culprit. I agree...I thought he wrote he had a .450 lift cam??
is the cam installed with any advancement in it??

 

That left-most advance curve is still looking the best to me.

 

well i got this motor out of a car. the guy i got it from paid a shop to build this car
specs were 1992 rs v6, pulled the v6 dropped in this motor and a build th350. plans failed and the guy just let it set in his shop. i picked up the car for a 1000 and got all the reciepts he paid over 2000 for the motor and another 1200 for trans. it had msd and all the crome u could want..

i did a compression test 175 across the board. it has a radical idle. came with a dyno sheet saying around. 350/400tq (can remember wife spilt water on it)
reciept says balanced/blueprinted cant really read anything elce.
the stam on the motor says 10066036

 

The 3896929 cam specs, according to an old TRW catalog, are 195 / 202 duration at 0.050", 0.390 / 0.410" lift, 112 lobe sep, ground 4 degrees advanced. It most definitely is all done by 4500, I can tell you from my own experience.

 

175 is good compression.

 

Sorry I missed this post. That's the L82 cam. It sucks, but should pull well to 5500.

 

ill change the cam if thats the problem... i just want more power

 

I may be reading your paper wrong, but to me it looks like you need the black springs. You should be getting around 20* more degrees of centrifugal advance by 3000 RPM.
With 14* initial, that gives you 34* total.

edit: The springs control the rate, but there should also be bushings. The bushings control the amount added.

According to your sheet, the black springs should be the weakest ones, and from the looks of it, use the smallest bushings.

 

34 is good for those older heads, but 14 initial is approaching the danger zone.
The L82 cam is what GM is currently using in the 290 HP crate 350, and it has a decently smooth idle. The old L82 was rated to 230 HP at 5200 rpm with stock exhaust manifolds.

 

Save the cam change until you first verify your current valve lift. If it's .450, then let's solve the problem before buying another cam.

 

think its time for a cam change and some boost.

 

It's nearly free to first verify your current cam. If it's as big as you think, then you need to solve the rpm problem before changing the cam.

 

block casting #10066036
heads# 93417369

Here's ALL of the info on that casting number i can find..

350 Cubic inches 4.00" Bore, 3.47" stroke
8.5:1 compression ratio.
250 HP @4300 rpm
350 ft. lbs of torque @ 3600 rpm
( These Numbers obtained with a Quadrajet Carb,1 5/8" headers , and an Edelbrock Performer intake part # 2101)

Engine consists of the following parts:

Block -part # 10066034, casting # 10066036
2 piece rear main seal 4 bolt main
Crankshaft- # 3932444
Nodular Iron 1985 and older flywheel bolt pattern.
Powdered Metal Connecting rods- # 10108688
Cast Aluminum Pistons-#12514101
G.M. High Volume Pump Oil Pump- part # 12555284
Hydralic Flat tappet Camshaft- #14088839
Intake Lift-.383" Exhaust Lift-.401"
Intake Duration @ .050"- 194 Exhaust Duration @.050"- 202
Lobe Seperation-112
This cam Has a mechanical Fuel Pump Lobe.
This is a low end Torque oriented camshaft.

Cylinder Heads- part # 14034808, casting #33417369, 1.94" Intake valve, 1.50" Exhaust Valve, 76cc Combustion Chamber, 7 Bolt style Exhaust Flange Standard, 85' and prior intake manifold bolt pattern. Perimeter bolt style Valve Covers. This head is very similar to the old #882 castings from the 1970's

This engine includes Painted Valve Covers, oil pan and Timing Cover. This engine is drilled for both L.H. and R.H. dipsticks. Plugs Are included to plug the side not used.Two timing pointers are also included, a pointer for a 6" balancer and a pointer for an 8' balancer.Balancer with 2:00 timing mark must be used with this engine in order for mark to line up with the pointer.
For most stock applications with HEI ignition, Base ignition timing should be set to 10 before top dead center (with vacuum advance disconected) Total ignition timing should be around 36 @ 3000 rpm.

 

yep. cam is too small. N/A I'd suggest a COMP X4-262H11. Boost I'd suggest a custom grind. a COMP 12-000-? With 5444 / 5070 lobes on a 114 lobe sep. Unless you want to go roller.

 

thats weird.. it has a better idle then my 272 cam did


i might just pull the motor and take it apart to see what its got..

maybe some new pistons for higher compression, bigger cam
i have a set of 64cc heads that i spent tons of time porting and i got manley 2.02 valves installed

 

there were only two bushings and it says to use the ones that fit. so i did the others did not. right now i am running the center springs. i was thinkin of going to the gold springs (the first line that starts at 2500)

 

Why?

 

i am not really sure just going to try it to see if it changes how it runs.. i would say its a cam but the motor does not seem to have any bottom end either? its just under powered

 

I told you, the solid black timing curve on the left is what you want. Do that, with 12 degrees initial, with the vacuum advance temporarily plugged. Then connect the vacuum advance to manifold vacuum.

 

what do you think the max cam lift i can go for?? around 500?

 

If you are camming mystery iron heads, best to stop around 0.480". You can spend $50 on a cutter / arbor combo to shorten your guides without pulling the heads, but stock heads don't flow any better at .500" than they do at 0.450".
The COMP Xtreme 4x4 cam, in the extra delicious 262 spec would be an amazing match for what you have. Atilla's air dyno has decreed it :-)

 

changed the springs in the distributer to the black ones, put the timing at 12 before, runs better and has better power. and will rap to 5 now. going to try a diffrent carb and see what happens

 

changing the cam to a bigger cam without upgrading the heads will only do so much. It's like if you have a decent intake, decent cam, and stock heads with headers is the same as running water through a water hose(intake), waterhose(cam), straw(heads) and back into waterhose(headers)...the motor only flows as good as it's worst spot.

 

I've heard the analogy (of the hose and the straw) before and I like it. It's a good way of explaining why the X4-262H11 is a realistic upper limit for stock smog heads with stock 1.94 / 1.50" valves, and dished pistons.