mutzi

hi forum-guyīs,

i have here in germany a 1978 olds delta 88 with a 403cui gas-engine and tune the car with:
- 1972 350cui 7a cylinderheads with 2" intake valve (buy from mondello)

- hydro-lifter and a JM18/20 cam (buy from mondello)
- edelbrock performer intake manifold #2711
- 750cfm edelbrock performer carburetor with electric choke (standard setting)

- edelbrock timing-chain, we put in the engine with standard position


mondello tell me on the phone i can use all original parts and than i have 350 to 400 horsepower

we work now on the car:
- mondello send me the false manifold for my rochester -> so i buy a edelbrock 750cfm
- we must drill the fitting pin-holes in the heads bigger
- he tell me he put inside the heads stainless steel valve but the 2" intake valve are oem-style
- than was the push-rods to short 0.118" - we plan the aluminum rockermount -0.039"
- we also change all bearings from cam, crank and rods.


then we start the engine with 12° initial ignition timing.
the car donīt have 300 horsepower i think.
- the valve and cam controlling runīs a little bit noise? - is that ok?
- so when the engine iddle in (P)arking position and i give full throttle the engine runs ok, but when i shift in D and give full throttle the engine rpm go down (the engine stall or stock)
- the same is when i drive an take a turn or stop then stall the engine or maybe go off.

- when i drive and the carburetor give the secondary gas - the engine rpm go down (stall) for a little moment
- when i give more throttle the engine smoke black
- before i tune the car the car needs 16 liter gas of 100km/ now the car need 30liter gas of 100km -< thats to much for the few horsepower more


- i send mondello this questions and he give me the 2 small information:
*set the total timing incl. initial at 36° to 38° -> we make that and the engine gives more power (that timing problem is clear)
* order the edelbrock calibration kit #1489 -> is that the only way to get off the problems with stall the engine? what for metering jet and rod combination i need?


edelbrock tell me the carburator is to big i need the 650cfm avs, but i have now the 750cfm.



can me help somebody?

Steve O

All good suggestions and that should be a good combo

What rear gear ratio/transmission is a TH350?/stock convertor???

If it has a stock converter and a 2 series gear that cam is gonna be a little sluggish on the bottom end.

The 750 carb should be perfect on that engine.

The 750 with the electric choke should have .113 main and .110 secondary jets an 7547 rods.

This carb is actually calibrated leaner than the manual choke version that is .113 main and .110 secondary with 7147 rods.

Either one of those calibrations on the carb should run good the 7147 rod would give better throttle response and the 7547 would get better economy...

Are you sure the choke isn't sticking closed? You could also check the floats and make sure their set right. There should be no higher than 7 PSI fuel pressure. Is it a stock fuel pump? Are you using a return line to the tank???

Your Q jet should bolt right on but the AFB is better suited for the cam your using.

What is the vacuum reading at idle???

Is it erratic??? it could have a vacuum leak at the manifold allowing it to suck oil into the cylinders causing the smoke.

Id pull the spark plugs and look for oil fouling or a lean condition.

While you have the plugs out check the cranking compression to make sure the cam is installed right...

It should have more than 140 psi, but not higher than 180 psi depending on your compression ratio...

As long as your rocker arms are adjusted to pre load the lifters .020-.040 a little noise is acceptable. That cam has fast ramps on it...

I would avoid Mondello, it sounds like Lynn screwed you on the valves

mutzi

the transmission is the TH350 with the original torque-converter.
gives a other converter more power of the rear-axle (which)?

i donīt know what for rear axle i have, i think the 8 7/8". as i buy a gasket i need the for the biggest axle from gm olds.

what is the AFB?

is no vakuum leak on manifold and no oil on the sparkplugs.
also the cam is installation of standard timingchain-set.

is a stock fuel-pump with return line to the tank.


you tell me the 7147 rod would give better throttle response and the 7547 would get better economy, but on the performer carb manual site 28 #1411 calibr ref chart is the 7147 for leaner gas stage?



because the engine smoke black -> we will change the mainjets 104 and the meteringrod 7042 or 7037.
the problem is the engine use now to much (25-30liter /100km).
the calibration is for stage 1 or 2 lean powermode and for stage 2 lean cruise mode.
BUT we check yesterday the sparkplugs and the color is white.
we will set the ignition timing from max 38° on max. 34° and than we will look again to the sparkplugs.
when the sparkplugs then also white - than is but to few (lean) gasoline, and we must donīt change the rods and jets for leaner gasoline -> we must go to stage rich.

Steve O

OOPs I was wrong on the calibration of that carb stock...

The 1407 manual choke has .113/107 jets, and the 1411 electric is quite a bit leaner with .110/107 jets...

The .113/.110 7547/7147 is what I use on a 455 with a slightly bigger cam than your 403

The Edelbrock carb is a copy of the Carter AFB, AFB stands for "Aluminum four barrel"

My experience with these carbs are they are close out of the box. The 1407 is a little richer than the 1411.

But neither would be rich enough to blow black smoke or stumble unless theirs something wrong...

Like the electric choke not opening or the floats stuck open by dirt in the needle and seat, floats set too high, or too much fuel pressure...

The 8 7/8 rear end is strong but theirs no aftermarket gears made for it so it sounds like your stuck with whatever's in there...

Id go with an 11" converter with about 2500 stall speed with that cam...

mutzi

ok thanks.
i will look on this weekend to the float seat and preasure and to the electric choke.
you drive a 455 big block that is not the same how my 403 small block.do you have also a TH350 transmission?
is the 11" converter with 2500 stall speed for this transmission also ok? give the 11" converter more power? what is than with the transmission - > than i must that TH350 stronger?

bye