[crazyhorse0686]

First let me just say this is a great fourm. Anyway..

I have a 1968 rocket 350 installed in a 1985 Cutlass Supreme. This was my first car and I did nearly all the work myself back in my 18-23 years. Now it's 10 years later and I unburied it from my garage and would like to get it running right. Here's where i'm at:

1968 Rocket 350 block
stock crank, cam, & heads.
Edelbrock Performer RPM Intake
Edelbrock 1407 750cfm carb
Stock TH400 Tranny & Torque Converter from a '77 Buick century
Headers
Hydraulic lifters, roller rockers
Factory rear from the 85 (was a 3.8 V6)

It was barely running when I pulled it out yesterday and bogged when I hit the gas. Last Night I replaced the plugs, set timing to 8 degrees, adjusted the idle A/F screws to about 1 1/2 open, changed to blue springs in the carb and set the pump rod to the bottom hole as per suggestions from other posts I found on this board and it's already a thousand times better. The problem now is it lacks power (I can't spin the tires the way I could when it was stock in the 68) And it still backfires every once in a while out both the carb and the exhaust. There is a small blowout in the header gasket from one of the backfires, but there are no other exhaust or vacuum leaks.

The distributer is HEI style with a vacuum advance and the advance line is hooked up to the proper, full-time vacuum port on the carb. I do not know what it's from but the guy I bought the 68 from said he put it in because he was sick of replacing the points. Interesting fact is that when it was on the stock engine the vacuum line was never hooked up. He said it ran better that way.

The jets in the carb are stock (.113 primary, .107 secondary)
The rods are not stock (stock was .071x.049 now .073x.052)
The rods made a difference for the better back when I put them in, but now that I'm trying to do things right I have no idea what rod/jet combination I should use. The boards say a manual comes with the kit but mine did not. I went to Edelbrock's site and they do not have it either.

I have a performer RPM camshaft that was never installed.

The stock 68 had a powerglide tranny and I used to be able to spin my tires off from start without even touching the brake. What do I have to do here to get some guts out of this thing. It's got a response similar similar to my full size van!

Thanks for your time time. I know it's a long post, but I've called around and no one locally could help me. I appreciate any and all suggestions.

 

[tm454]

OK...you started this car up after 10 yrs of sitting...did you replace the fuel and fuel filter? Are you ready to rebuild the carb..it probably needs it as there is probably gunk in it from sitting. I don't remember what a 350 rocket timing is supposed to be set at with the Electronic ignition/HEI so you'll have to ck on that one. Sounds like the timing is off...does it deasel when you shut it off?? Good luck betting it back on the road!!


Rat Rods Rule!

 

[crazyhorse0686]

OK...you started this car up after 10 yrs of sitting...did you replace the fuel and fuel filter? Are you ready to rebuild the carb..it probably needs it as there is probably gunk in it from sitting. I don't remember what a 350 rocket timing is supposed to be set at with the Electronic ignition/HEI so you'll have to ck on that one. Sounds like the timing is off...does it deasel when you shut it off?? Good luck betting it back on the road!!


Rat Rods Rule!

Well, it was started and driven about 3 miles in 2001 when it was moved to my new garage.

It ran out of gas while I ws running it and it now has fresh 93 in it.

Honestly it sounds great, it doesn't ping or diesel. It does smell like it's rich. No black clouds like before I did everything last night, but enough to fume up the garage with all the doors open.

I'll look into the timing - I suppose it's a good place to start since it was the first thing I did. I'm also suspecting fuel pressure. It's the stock pump. Anyone know what a 68 pump might push? It had a quadrajet on it stock. Is there anyway to determine that without a fuel pressure gage? Thanks again for all your help. Your expertise is much appreciated.

 

[Robinson Robin]

With out using a fuel gage it will be difficult to judge how much pressure you are getting how ever it should be in the 7-10 psi vicinity. It sounds from the backfiring you describe as if you may be getting a lean spot, I might be suspicious of the accelerator pump. Its possible the discharge tube it partly restricted or the rubber seal on the pump isn't sealing, have a look down the carb as you work the throttle and make sure you have a healthy looking shot of gas coming out.

 

[docvette]

Some things to look at...

Doc here imp:

After 10 years of sitting, some of things I would look at, or do are:

Check Inside The cap AND Coil area for alien lifeforms making a home in there, This will cause arcing where it shouldn't..

Check your mechanical advance for rusted shut condition, maybe give it a VERY tiny , tiny drop of oil on the pegs and exercise it by hand a few dozen times...

New oil, Filter would be good...If you haven't already done that..may It may be thin enough or just thick enough to not have the ooomph to pump up the lifters all the way...

Gas in the oil... a LEAKEY pump diaphragm would give you low pressure, & bog..It may or may not leak into the crankcase...Your choice here, buy a pressure/volume gauge, or just replace the pump at about the same cost...and / or test the pressure and volume.

Partially Clogged Fuel filter or "Gators" (Dead, solid gummy Gas) Clogging the pick up screen in the tank.. Back blow or pull the sender/pickup housing...

10 year old plug wires just can't be a good thing either...dance of the sugar plum fairy...CROSSFIRES! If you haven't already done so, I'd replace them.

Does That Ol' Rocket have an EGR? It may be bad or leaking too (accounting for the random backfire)

Check your timing and set it properly, and also check the back-slap (turn the engine slowly by hand and watch the rotor)on the Timing chain and distributor...(you might have to do gears and chain, and finally use that cam you bought so many years ago!)

Good luck!

Doc imp:

 

[crazyhorse0686]

Thanks for all the suggestions so far, but nothing has really helped. I fooled with the timing but it seems to be best at 8 degrees. The oil seems to be in good shape. Still clean and no sign of gas. The cap and rotor are still in pristine condition. The plug wires have no corrosion or anything to suggest that they are bad. It does not not seem to have any lack of fuel. I have a clear filter by the carb and it is always 3/4 full while running. The timing gears and chain were replace with an Edlebrock set back when the intake and carb were put on so there is no slack in the chain.

Anyone have any suggestions on the rods or jets in the carb? I can do trial and error with the rods, but doing that along with the jets results in many combinations - it just doesn't seem logical. How 'bout the springs? The blue springs made such a difference, but are they right for this application? I've been searching for three days now and have an email into edlebrock but I cannot find any suggestions anywhere. I have the 1480 calibration kit but I cannot find any Manual for it. Edelbrock only has instructions for the 1495 or something for marine applications.

An old friend reminded me that I didn't really know what I was doing when I set the rocker arms. If memory serves me right I got them all snug, started the engine, tightened each one till it stopped tapping and then another 1/4 turn. Does this sound right for roller rockers with hydraulic lifters?

Has anyone worked with a powerglide and a TH400 on the same engine? Is the TH400 more desirable in this application? At the time I was told it was the best but the powerglide seemed so much better off the start. Is it the rear that slowing me down?

I have so many questions. Thanks to everyone that has taken the time to give me advice.

 

[crazyhorse0686]

Well I finally got the tires spinning, but only if I use the brakes. I changed the rods to .073x.047 and it seemed to double the power I had before, but I still don't get that snap your head back startup that I'm looking for. High end, however, is pretty good. The TH400 slips into high gear around 65 and she takes off to over a hundred with a lot to go (I'm testing on a back roads around town so I can't let go much further then that). I then changed the rods to a .069x.047 and lost some power. I still got some backfires, but now it seems to only be out the exhaust. Every time I mess with the timing it only makes things worse. Should I try these rods with different color springs?

How much of a difference will the Performer RPM cam make? Am I wasting my time doing all this work with the stock cam in there?

It's nice to go fast, but now that I'm older I'm more interested in
low-end jump.

So far all the suggestions have been great! Thanks again for your input.

 

[MRGM]

www.oldspower.com :welcome:

there are many people who have done this swap. have you checked all your fluids, including the rear. just makin sure. do not want that thing leavin you stranded out somewhere while your tunning it.
------------
am i bad for posting that link :spank:

i post this site over there in my sig.

 

[crazyhorse0686]

Thanks for the link! What a great olds site. Got some great input on drivetrain and such, but I didn't get much on tuning the edelbrock carb or setting the rocker arms. Any help on that would be GREATLY appriciated.

 

[MRGM]

Thanks for the link! What a great olds site. Got some great input on drivetrain and such, but I didn't get much on tuning the edelbrock carb or setting the rocker arms. Any help on that would be GREATLY appriciated.

sorry, we be a people who prefer the superior qjet imp:

 

[crazyhorse0686]

Anyone out here have any suggestion as to what range stahl convertor I should use with this setup?