1973 RR pretty much a dog

[Barry_Calgary]

My 73 RR has a pretty much stock 1978 440 engine with auto and I'm guessing a stock rear end. It does have a dual plane manifold and an upgraded ignition. However it's a complete dog, I was expecting it to a least spin the tires and have some power. I have checked the timing, the carb is a carter AFB and seems to work fine. The RPM's when you punch it sound great but just seems to have about half the power I expected.
Any suggestions or comments appreciated.

 

[Richard Cranium]

I was expecting it to a least spin the tiresr.

Any suggestions or comments appreciated.

Wait till winter & drive it on snow covered roads.

 

[Budnicks]

We really need to know a little more information, than just a 73 RR with a 78 440ci engine...

But the 1978 440ci was a Low compression & low HP, it's was like in reality less than 8:1 compression...
Was the 440ci out of a RV ?? or Truck, the 78 440ci RV versions were low HP turds,
they had really restrictive cylinder heads & exhaust manifolds,
little intake & exhaust valves, small camshaft, weak insufficient low rpm rated valve springs...

but it still should be able to turn/burn the tires, tuned properly...

& the 73 RR might or could possibly have freeway/high gears {2.70-2.90's range, at-least 3.23:1 maybe, if your lucky}
what style rear end & gears does it have ??

all this aiding to the feeling of gutless or being a complete dog,
especially with a tired old smog era low hp 1978 440ci accompanied with a stock auto & freeway gears...
{but "should" still turn the tires}

A free flowing gauze type air cleaner, on-top of a decent aluminum 4bbl manifold, {you say you already have the carb & ignition}
a set of 1-3/4" to 1-7/8" headers {even shorty headers will be allot better},
at-least with some free flowing 2.25"-2.5" mandrel bent exhaust tubing, with an X or H-pipe, with some free flowing mufflers
& a set of steeper gears {at-least like 3.55:1-3.73:1, to help move the heavy car} all these things, will all help...

If it was an old RV {especially} or truck 440ci the heads are a big part of the limitations on HP,
a better set of heads, even some cheap stock cast iron 1968-70 906 castings,
with bigger intake & exhaust valves, better springs & then get the proper style camshaft,
good lifers & pushrods for your specific type combo & your specific needs,
that would really help to "wake up" that old 1978 440ci...

 

[HT413]

Well its not all bad. My low compression 413 (which i measured to be 7:1 :eusa_wall will spin my 30x12.5" wide ET streets (and will boil them with my line lock :frog.

Im running a 727, 4.10:1 gears, 906 heads, RPM intake, holly vac secondary 750, el cheapo headman headers, MSD 6AL ignition, and what im pretty sure is a Comp XE268H cam.

I have a 440 i'm planning on building to replace it, but that low compression RV motor really isnt too bad at all.

 

[Photon440]

Have you done a compression test? I know you said that you checked the timing, what was it at different rpms (idle, 1200, 1600, 2000 etc) Is there any chance that someone has been inside the engine in the past and something like the cam timing is off? As already asked, what's the rear diff. ratio?

 

[Barry_Calgary]

Thanks, all I know is that the previous owner told me it was a 78.
Block number shows 4006630. Is there an easy way to tell what gears are in it?
Off the line is does have some jump, the tranny shifts quickly and by 60 mph
It's around 3000 rpm.
It's a bit of a guessing game when you don't know much about the car,
It may take some time to find out where the issues are.

 

[HT413]

60mph at 3000, that's where im at with my 4.10's and 30" tall tires. Sounds to me like you have 3.73's at LEAST, depending on tire size. FWIW, the original owner had mine like 15* retarded instead of advanced. Was a DOG and overheated pretty quickly.

 

[Uberbricky]

I put lighter springs in my distributor, 34 deg total timing and did a rod swap in my edlebrock 750 and it really woke up my 73 440, also in a 73 road runner.

Likely a little tuning will change things for you

 

[bobtile]

Well its not all bad. My low compression 413 (which i measured to be 7:1 :eusa_wall will spin my 30x12.5" wide ET streets (and will boil them with my line lock :frog.

Im running a 727, 4.10:1 gears, 906 heads, RPM intake, holly vac secondary 750, el cheapo headman headers, MSD 6AL ignition, and what im pretty sure is a Comp XE268H cam.

I have a 440 i'm planning on building to replace it, but that low compression RV motor really isnt too bad at all.

I'll be damned if I'm going to sit here and let you talk about my headers that way. Anyway, it should have enough torque to spin the tires. If not, put snow tires on. That should fix the problem.