Heads and manifolds

[UKSquarebody]

Hi all,

Getting a bit confused here in the U.K.
My 87 squarebody has been messed about with long before I bought it.
It’s a small block, with a 1406 Edelbrock on it.
I’ve not been able to drive it much, but now I am, I notice how much it bogs down on acceleration, idles lumpy, and has no low end torque.
Looking at it, it has a Holley Street Dominator single plane manifold on it. Everywhere I read says this is not ideal for a street car - which this very much is.
So, I want to fit and Edelbrock performer to it before putting on a rolling road for tune.
So I have checked my head numbers - 33417369. These are apparently Mexican 1987-96 heads.
So. - post 1986 heads, with vertical centre bolts?
Yet, as you see on the pictures, my inlet bolts are all at the same angle.
So what do I order?
Which Edelbrock manifold should I be getting?

Any help,
Cheers,
Keith

 

[mlsceo]

I would check with them to be sure but looks like the 2104 from Summit Racing Equip. is what you're looking for.

 

[Hilllbilly]

33417369...90-up...350..........Gen.I Goodwrench crate motor,"Hecho en Mexico", 76cc

Replacement Crate motor.
Looks like standard '55-'86 bolt angle

 

[Ricko1966]

If you get one for early heads it won't matter. The early manifold you can slot the middle bolt holes with a die grinder or dremel. to fit late heads. Telling you this,because I'm sure shipping twice and 1 back is expensive. Buy the early one but it won't be a big deal if it's wrong. I'd be looking at the camshaft profile and rear gears real hard, they are going to change your drivabilty more than the intake. If someone had too much cam and not enough gear in the truck you are never going to like it. Here's a little tip for you,lumpy idles aren't caused by intakes. They are caused by big cams or intake leaks.

 

[UKSquarebody]

Really appreciate the feedback.
Will check on the cam.
It idles fine on start up.
Pull up to traffic lights in gear when warm and it lumps about like it’s gonna stall.
It splutters on take up, and when I say no low end - it feels kinda like it wants to go, but doesn’t. Hesitates a lot. And it drinks - a LOT. I am sure it is fuel related.
Everywhere I have read says single plane is not suited to road cars, and causes these kinda symptoms.
I’m a body guy, not engine guy.
Trying to minimise the work my tuner needs to do. I will talk with him this week.

 

[Ricko1966]

Really appreciate the feedback.
Will check on the cam.
It idles fine on start up.
Pull up to traffic lights in gear when warm and it lumps about like it’s gonna stall.
It splutters on take up, and when I say no low end - it feels kinda like it wants to go, but doesn’t. Hesitates a lot. And it drinks - a LOT. I am sure it is fuel related.
Everywhere I have read says single plane is not suited to road cars, and causes these kinda symptoms.
I’m a body guy, not engine guy.
Trying to minimise the work my tuner needs to do. I will talk with him this week.

You need someone who knows how to tune it,get the timing right,get the carb set up right. If it idles fine on start up,then develops the problem I no longer suspect too much cam,maybe but you won't know until it's tuned right. It is not the manifold though. Maybe an intake leak but not the manifold. Single planes are a little more soggy down low,but it should idle fine,and once you are into the cams power range should run good. I've run single planes on daily drivers with fairly large cams to and from work daily.

 

[UKSquarebody]

You need who knows how to tune it,get the timing right,get the carb set up right. If it idles fine on start up,then develops the problem I no longer get suspect too much cam,maybe but you won't know until it's tuned right. It is not tge manifold though. Maybe an intake leak but not the manifold. Single planes are a little more soggy down low,but it should idle fine,and once you are into the cams power range should run good. I've run single planes on daily drivers with fairly large cams to and from work daily.

Appreciate the help.
Will get it to my tuner this week.

 

[Ricko1966]

Really appreciate the feedback.
Will check on the cam.
It idles fine on start up.
Pull up to traffic lights in gear when warm and it lumps about like it’s gonna stall.
It splutters on take up, and when I say no low end - it feels kinda like it wants to go, but doesn’t. Hesitates a lot. And it drinks - a LOT. I am sure it is fuel related.
Everywhere I have read says single plane is not suited to road cars, and causes these kinda symptoms.
I’m a body guy, not engine guy.
Trying to minimise the work my tuner needs to do. I will talk with him this week.

Make sure the choke is opening when the car warms up. A closed or partially closed choke would explain a lot.

 

[Grit dog]

There are plenty of things I’d check before ripping the top end off the engine. Whole thing looks pretty new and clean and we don’t know the history but it’s reasonable to believe it ran well at some point unless you just cleaned it up and put that new carb on a non running engine and verified nothing else.
A new carb will run fine out of the box. Maybe not optimal if you’re really dialing it in, but I’d guess 90% of aftermarket carbs get tossed on and run for years with absolutely no tuning. At least a few I’ve installed have.
I’m assuming “tuner” is British for mechanic?
If so mechanic should start with timing/advance, vacuum, choke etc.

 

[ali_c20]

My approach would be:

Vacuum leaks.
Choke function.
Timing. Timing has to be set correct. Without proper timing carb adjustment is pointless.
Pull Spark plugs to see if you're pig rich or lean.
Idle.
Carb tuning. (Fuel pressure, float level, rods/jets etc.) A wideband o2 sensor helps a lot when doing this.

 

[UKSquarebody]

Thanks guys.
‘Tuner’ - dyno, rolling road. Not sure what you’d call them in the States. They aren’t general mechanics.
I’m leaving it be until Jon can run it on the dyno and see what it’s doing - when and where.
I’ve never had it run great, but I’ve only had a it run a few hundred miles in 2 years!
The previous owner started out down the drag strip route with it. I just want a smooth daily driver work truck.
It had a big Holley double pumper drowning it, with MSD fully programmable etc.
All on a pretty standard Goodwrench 350 by the looks of the numbers on the castings, with a 700r4.
Now has a 1406, standard MSD HEi - and is way more drivable then when I bought it.

Will report back after the dyno.

 

[75gmck25]

The GM crate will have a mild cam with duration about 195/202 degrees @ .050. It also has low compression heads (maybe 8.2) that don’t flow that well.

Typical upgrades
- Good dual plane intake (Edelbrock performer, performer rpm, or equivalent is least expensive)
- advance the base timing to at least 12, and maybe closer to 16
- make sure the HEI adds 18-20 degrees from mechanical advance. For better acceleration, modify the advance to get mechanical to come in earlier, maybe by about 2000 rpm (stock may be more like 3k rpm)
- make sure vacuum advance adds about 18-20 degrees. You need this for good highway fuel economy.

-1406 should work well, but often needs step-up springs that are rated for a higher vacuum. IIRC, stock springs are 5” rating and the Edelbrock tuning kit goes up to 8”. Higher rated springs allow the rods to get into power mode earlier as vacuum drops, which often resolves a mid-range bog. Also make sure the transfer slot exposure is mid range (slot will look square) and then set the idle mixture for best idle. This usually helps smooth out the transition from idle to power mode..

- add a low restriction exhaust, and headers if your budget allows
- next step up would be a cam in the range of 212 to 214 duration @ .050. This is about the most you can go and still work with the original smog-era heads and your heavy truck. Higher duration than that may work, but will usually take away low end torque and lower the gas mileage.

Make sure your mechanic knows how to adjust the TV cable on the 700R4. A mid-adjusted cable can destroy a 700R4 in a short time.

 

[UKSquarebody]

The GM crate will have a mild cam with duration about 195/202 degrees @ .050. It also has low compression heads (maybe 8.2) that don’t flow that well.

Typical upgrades
- Good dual plane intake (Edelbrock performer, performer rpm, or equivalent is least expensive)
- advance the base timing to at least 12, and maybe closer to 16
- make sure the HEI adds 18-20 degrees from mechanical advance. For better acceleration, modify the advance to get mechanical to come in earlier, maybe by about 2000 rpm (stock may be more like 3k rpm)
- make sure vacuum advance adds about 18-20 degrees. You need this for good highway fuel economy.

-1406 should work well, but often needs step-up springs that are rated for a higher vacuum. IIRC, stock springs are 5” rating and the Edelbrock tuning kit goes up to 8”. Higher rated springs allow the rods to get into power mode earlier as vacuum drops, which often resolves a mid-range bog. Also make sure the transfer slot exposure is mid range (slot will look square) and then set the idle mixture for best idle. This usually helps smooth out the transition from idle to power mode..

- add a low restriction exhaust, and headers if your budget allows
- next step up would be a cam in the range of 212 to 214 duration @ .050. This is about the most you can go and still work with the original smog-era heads and your heavy truck. Higher duration than that may work, but will usually take away low end torque and lower the gas mileage.

Make sure your mechanic knows how to adjust the TV cable on the 700R4. A mid-adjusted cable can destroy a 700R4 in a short time.

Thank you - great advice.

 

[Grit dog]

Thanks guys.
‘Tuner’ - dyno, rolling road. Not sure what you’d call them in the States. They aren’t general mechanics.
I’m leaving it be until Jon can run it on the dyno and see what it’s doing - when and where.
I’ve never had it run great, but I’ve only had a it run a few hundred miles in 2 years!
The previous owner started out down the drag strip route with it. I just want a smooth daily driver work truck.
It had a big Holley double pumper drowning it, with MSD fully programmable etc.
All on a pretty standard Goodwrench 350 by the looks of the numbers on the castings, with a 700r4.
Now has a 1406, standard MSD HEi - and is way more drivable then when I bought it.

Will report back after the dyno.

You’re saying you believe it’s a run of the mill low comp milquetoast 350. Fwiw, may consider foregoing the the expense of dyno runs and “a tuner” (person) in favor of just getting it running right.
Maybe just me but I don’t see the value of tuning and dyno to get a basic low power small block with a 500cfm carb and 8.x compression just running smoothly.
I think the roi is very low.

 

[Ricko1966]

You’re saying you believe it’s a run of the mill low comp milquetoast 350. Fwiw, may consider foregoing the the expense of dyno runs and “a tuner” (person) in favor of just getting it running right.
Maybe just me but I don’t see the value of tuning and dyno to get a basic low power small block with a 500cfm carb and 8.x compression just running smoothly.
I think the roi is very low.

I think he doesn't know enough about the ins and outs of American V8s,timing needs,how to set up the carb, how to diagnose problems etc. etc.