matt_82transam

- Comp cams 262h cam .462/.469 lift
- Accel 8.8 wires and 45 000 volt coil
- GM HEI distributor with moroso medium guage springs (moroso curve kit) gives under 14 degrees advance under 4800rpm
- Holley (red) electric fuel pump , low psi for carb
- 1405 Edelbrock 600 cfm carb w/manual choke
pwr range 1000-5500rpm
- flex fan (larger diameter)
- Edelbrock EPS intake manifold with slightly opened up ports.
pwr range 1000-5500rpm
- "462" double hump heads , slightly ported and smoothed ports , 1.94/1.60 valves 64cc chambers with flat top pistons give around 9.8:1 compression

- 1969 350 4 bolt main block
bored 0.030 over
High volume oil pump
Cast aluminum flat top pistons with 4 dish reliefs
stock oil pan

- cam installed 4 degrees advance which should put 1200-5600 rpm power range to around 1000-5500 rpm

-open element air filter
- heddman headers 1 5/8'' shorty headers
- custom 3'' single exhaust
- dynomax super turbo muffler
- roller tipped 1.5 rockers
- th350c transmission
-2.93 posi rear end

-timing is set to 10 degrees initial advance
-not sure on how much vacuum advance
-10'' of vacuum at 1000rpm coming from carb


i have a lot more power after 1500rpm but from a dead stop I cannot break the tires loose except for the odd chirp????

five7kid

iTrader: (14)

Exactly what cam is that? I'm not the most Comp-literate out there, but I can't find anything that matches that description.

What does your converter stall at?

You aren't getting much advance, and it's taking forever to come in. You're about 10-12 degrees short on total mechanical, and it should all be in by no more than 2500.

That rear end ratio isn't exactly jack rabbit material (I should know...). That along with the TH350 1st gear and low stall, ain't gonna be a lot of chirpin' goin' on.

Besides, not breaking the tires loose means you have a good balance of power and traction.

matt_82transam

i was told that i should put the medium guage advance spring in because the lightest gives way too much advance under 5000.
The lightest give around 23+ degrees before 4500rpm.
I talked to alot of other people and we reached a conclusion that the tranny is the problem. ?It doesnt grab very good at all just slips at WOT and makes a loud howling sound.

I am looking at getting a th350 long shaft NON_LOCKup rebuilt with better clutches and shift kit as well as 2100stal converter.

Also soon after that, 3.42 gears should complement everything nicely.

Stekman

five7, that is the XE262h series camshaft.

something like 1300-5500 rpm range
262/270 adv. duration
218/224 @ .050"
.462/.469 lift with 1.5 ratio rockers
110 LSA

Its been a bit since ive looked at that cam grind, so the numbers may or may not be accurate. But it is the XE262h.

GASGZLR

I vote you put the cam back in straight, most cam manufacturers grind their cams with a slight advance into them thses days, especially the XE series from comp.

F-BIRD'88

Torque converter stall speed is way too low for the cam duration. The torque converter may not even be functioning right. (multiplying torque at launch)
Broken converter fins, broken stator.
sounds like the trans is hurting.
Rear gearing too low. 3.73's are just right.
and a 11" 2800stall converter.

The ignition timing needs to be worked on.
You need to do more than just install moroso springs.
Get an advance timing light or timing tape and see how much total timing you have.
You want 32-36 degrees mechanical advance at about 3000. It should not advance further beyond 3000 rpm.

you want to use more initial advance with the same 32-36 total advance. This involves limiting the advance travel.
14-16 initial +20 degrees distributor advance =36 degrees at 3000

Vacuum advance is a separate issue. use ported vacuum. an aditional 15 -20 degrees vacuum advacne at highway cruise speed will work nicely.

Even thou you have "64cc heads" and flat tops pistons
your actual compression ratio is probabily a lot lower than you think. Heads can and do range from 62 to 68cc's
those pistons can be .045" or more below deck at TDC.
could be as low as 8.8:1

the carbs accelerator pump may need tuning and tweeking.
I second moving the cam back to the cam card specs.

matt_82transam

i was also thinking of switching to a holley carb or to an edelbrock 650 AVS.

I was wondering what kind of changed to (linkages,lines, brackets,etc) I would have to make to switch from my edelbrock 600 1405 to a holley 650dp.

If everything was fine and I swapped to the 650dp, should there be a big power gain , how would gas mileage be?

five7kid

iTrader: (14)

Linkage shouldn't be a big hurdle. They're basically the same. Cable studs & brackets should be the main change-over items.

You probably won't see any peak power gain with a Holley DP over the Edelbrock. But, you may see more "area under the curve".

matt_82transam

I guess i am being hinted that changing from my 600cfm edelbrock to a holley 650dp wont exactly give me the night and day performance difference i am expecting..
ok...what else could be the problem.
One of the guys from a performance shop told me he thinks it has something to do with spark. He said to try any other distributor and note any differences. He said even though I have a higher voltage coil and different weights and springs for my advance, there could just be some internal problem in the dist. which is restricting a lot of energy to burn the fuel...
*that I didnt try doing so that could be a possibility*

However personally I am leaning towards the transmission. This is because I have had over a dozen experienced people take a look at the setup and had a test drive..They say the engine sounds very strong and perfectly healthy. I remember when I had my 305 in my car and the th-200c, off the line the tires would roast(understandable due to low low stock power range) however when It would shift , every change..1-2..2-3.. would result in a loud chirp and a nice snappy shift.
NOW for my th-350c, from 2-3 ...at the point it should shift(around 2800rpm) it stays there for 2 seconds and revs up slightly higher and then shifts with no physical evidence of a shift except for a very slow pull while rpms are going up.


Basically I think there is ALOT OF SLIPPAGE.
If anyone can think of another possibility that is stopping this beast from showing its guts, please reply.

matt_82transam

ok I just swapped the old distributor for a rebuilt all GM distributor.
The GM coil was faulty so i put on my accel hei super coil.
I didnt swap the moroso weights or springs yet but there isn't really an difference

So the dist. hunch is crossed out.

I will keep everyone posted when I put a different tranny in.

RB83L69

• Carb is too small
• Fan drinks about 15 HP
• Headers are too small
• Open element is costing you power
• Those gears are for grocery carts, not a car that's supposed to be quick
• HV oil pump is throwing away power needlessly
• The 350C converter (more gas-mileage grocery-cart stuff) is about as anti-performance as you can get; a regular 350, with a 2500-2800 sort of stall, would make the car radically different; I don't know if anyone can even make a stall for the 350C

That cam and those heads should work reasonably well together; but advancing the cam isn't necessary. I'd put it back straight up.

The biggest problems are really the gears and the converter. If it comes down to an issue of triage, I'd recommend dealing with those things first. The engine while maybe not optimum looks like it's at least not severely deficient. The other things are.

If you switch carbs and have to pay money to do so, go to a Holley.

For dist tuning, my first pass would be to set the static timing at about 10° with 24° of mechanical, starting at about 1200 RPM and reaching the full 24 at about 2800. Not too much different from F-bird's curve really. I wouldn't worry too much about tuning the vacuum advance until you get the mechanical part working right.

matt_82transam

RB82L69

Thanks a lot for the reply. I am really leaning on returning my 600cfm edelbrock carb and getting a 650 AVS.
As for advancing the cam 4degrees, can I leave it the way it is because if it isnt really going to have a huge impact ide rather save the hassle.

On the transmission side I agree with you 110%.
I have a crapola tranny. When I shift it slips like you wouldn't believe. So would a different tranny solve the off the line issue.
Well, a friend that works at a tranny shop is rebuilding me a th350. It is the same 9'' long shaft design but is non-lockup and has a 2200 stall converter and the internals of the tranny are getting hi performance clutches and other solid parts.
Also a shift kit is coming in.

As for gears i decided 3.73 will probably make my power range go by way to quickly and the street milaege will be terrible,not that I care about gas milaege.
However I decided on 3.42 gears.

Im surprised you mentioned that those heads should work fine with the cam...atleast i matched something right

But basically within a few weeks I will tackle the carb issue and get that 650AVS and the tranny will follow..

Keep up the reply's ....I need to learn from your past setups.

AM Racer

Going up in carb size does nothing for improving off the line performance.
I'm not understanding the no difference in the Moroso springs and weights. How can they be the same as the stockers?
Did you degree the cam or just toss it in on the marks?

matt_82transam

I just bought the 650 THunder series because I have a little more tuning features like the secondary timing.
I didnt swap the moroso kit from the old dist into the new one yet.
however i will do that today.

**I have a choice of 3 spring guages***
which one should I install?

This is a table of the degrees of advance I get from different guages

(rpm x 100)
15rpm 20rpm 25rpm 30rpm 35rpm 40rpm 45rpm 50rpm
light 6* 8* 14* 16* 18* 20* 22* 24*
Med 0* 2* 4* 8* 10* 12* 14* 14*
Heavy 0* 0* 0* 0* 4* 6* 8* 10*

I am sure I have around 10* vacuum advance
I have 8* initial

GASGZLR

I found that many of those spring kits don't advance like they say they do. I ended up going with stock weights that were very heavy and stiff springs. i found it easier to control the rate of advance with these. But the best advice I can give you is to test them all, most likely the lightest ones will be so light that your car won't even hold the initial timing stable, it will bounce around. Put some on then rev the motor looking at the timing light, or have some one rev the motorto 3000 and play with different combos of springs to get all the timing in by 3000. Don't be afraid to put different colored springs on at the same time, IE one medium and one light. You will find that the springs don't do what they say they do.

AM Racer

I'd give the lightest set a try and set the initial for 12~14 degrees.
Also, forget about the vacuum advance since it'll put over 50 degrees.

matt_82transam

ok I installed one light spring and one medium spring.
The carb is installed along with a new fuel filter.
I didnt adjust the carb yet trusting the preset tuning for the time being until I have time to tune it well.
With the carb and curve kit, I definately feel a bit more torque and I can actually spin the rears slightly.
However from a dead stop WOT there is a 0.5 second (delay/bog) like it is getting too much fuel) then the pull starts.

But to make this message short, the carb and the spring combo. is a good start so far.

I am just waiting for a tranny to be built with 2200stall conv/racing clutches, and shift kit.

Then right after that 3.42(im 75% sure) are coming in.

By that time my local track will be open and I will tell everyone my times.

until then , thanks for all the replys and If you have an opinion not already stated in this post..PLEASE tell me.

AM Racer

Work on the accellerator pump. experiment with moving the pump rod position from one extreme to the other. Not knowing the particular carb you have in detail, I don't know how much latitude of adjustment you have.

matt_82transam

thanks for all your replies. i will try adjusting the acc. pump as soon as i get my bird running again.
Yesterday I had an engine fire!!!AHHH
I stopped at a light then when it turned green I floored it...after that it backfired like crazy through the carb. I tried starting it again but nothing.
Then when I pushed it to the side of the road i saw flames coming out of the cowl. I thought that was it... $5000 down to the ground.
I open the hood and there were huge flames coming out of the carb. So i took my shirt off and blocked off the carb. It burned for around 10 minutes before it finally died out..just when the fire dept. came..what amazing response

anyways I didnt get too much damage, the open element is totally black and the huge 14x3 element is just a plastic ring melted into the concrete. The carb is basically black inside. Doesnt seem too bad, just might have singed the top plate gasket a bit but generally the carbon can be cleaned up.

However I thought it was a timing problem as in the distributor.
But when I got it running for 2 minutes today, and set the timing on the newer distributor I put in, it was exactly 8* initial then it died. When I went to restart it again..a HUGE flame came out of the carb but thankfully no fire. I dont understand ... I put in a newer dist. which I thoroughly checked over , I changed all of the rocker nuts so there is no chance of the used ones backing off.
All of the valves ( from the open valve cover view) seem to open fully and close fully. Plug wires , firing order , plugs , cap , rotor, all checked over and perfect.
BUT it has to be something with timing because if the backfire through the carb contained the compressed air fuel mixture from that particular cylinders compression stroke...the intake valve had to of been open at the wrong time , or the valve timing was correct but the coil decided to fire at the wrong time????

Well if this helps... I put my finger in the #1 spark plug hole and when the balancer read 0* tDC I felt compressed air which makes sense and when the balancer mark was at 0...I took the dist. cap off and the rotor was pointing exactly at the #1 terminal.
Firing order correct 1-8-4-3-6-5-7-2

The machine shop assembled the bottom end and I told them to install the cam 4* advances due to the theoretical stretch of the power range to start around 200rpm sooner.

I am thinking that maybe something is wrong with the timing chain because only now this is happening when the motor has 1400km on it compared to the first couple weeks of driving when everything was still stiff at around 700km.
However when I was setting the base timing the mark was perfectly stable..it wasnt bouncing around like a symptom of a stretched chain.

I know the first answer to the popping problem is carb related..however the carb has nothing to do with the air fuel charge in the cylinder escaping through the carb.

The only thing I am suspecting that seems plausible is that the coil is defective. It is a 6 month old ACCEL SUPER HEI COIL.
I think this because when the intake stroke on a particular cylinder is occuring(in. valve open) the coil is for some reason getting a signal to fire a particular cylinder which is causing the existing raw fuel mixed with the air(that is only supposed to come in) to ignite and leave the cylinder and exit out carb.

If anyone else has any other possible ideas..please tell me.
I DONT WANT ANY MORE FIRES hot hot hot:lala:

matt_82transam

well I made my final decision. I am going to take the 350 out and thoroughly go over it. By that I mean taking the timing cover off and checking the chain ,sprocket etc.
I will also take the intake off and the cylinder heads and check the valves for any bad signs such as cracks.
I will also take out my cam and check my lobes to make sure the initial cam break in procedure went smoothly.
Then I will install it from the former 4* advance to 0* as recommended by comp cams.
I will also try to swap the PERFORMER EPS for a PERFORMER RPM (I really want an air gap and heard a lot of positive things on them so I will go with) the PERFORMER RPM AIR GAP.
This will match the power curve in the following manner.

RPM INTAKE= 1500 to 6500rpm pwr range
262 cam 0* = 1300 to 5600rpm pwr range
650 carb = should be plenty. 2500 stall converter (im leaning on maybe 2200 or 2400..not official)

matt_82transam

well I made my final decision. I am going to take the 350 out and thoroughly go over it. By that I mean taking the timing cover off and checking the chain ,sprocket etc.
I will also take the intake off and the cylinder heads and check the valves for any bad signs such as cracks.
I will also take out my cam and check my lobes to make sure the initial cam break in procedure went smoothly.
Then I will install it from the former 4* advance to 0* as recommended by comp cams.
I will also try to swap the PERFORMER EPS for a PERFORMER RPM (I really want an air gap and heard a lot of positive things on them so I will go with) the PERFORMER RPM AIR GAP.
This will match the power curve in the following manner.

RPM INTAKE= 1500 to 6500rpm pwr range
262 cam 0* = 1300 to 5600rpm pwr range
650 carb = should be plenty. 2500 stall converter (im leaning on maybe 2200 or 2400..not official)

AM Racer

If the coil only fires when voltage is received, then why blame the coil?
Is it supposed to send a signal back to the distributor saying, wait a minute, not so soon?

matt_82transam

TRUE TRUE

Well there is only one thing to do.
This weekend I am going to take out my engine and tranny to get everything ready for the built up performance th350 non lockup.
I cannot wait

While the engine is out i will take out the cam and check the lobes for any damage for initial break in. I will also install it 0*.

I will keep you posted on my latest findings.