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Username Post: Rate this setup for my '56        (Topic#345402)
regan56 
Very Senior Member
Posts: 1522
regan56
Loc: Regina SK Canada, eh!!
Reg: 12-09-02
06-13-17 07:09 AM - Post#2695776    

327 with a mild-to-mid level comp cam (cant recall #), 750CFM Q-jet, TH350, 3.08 gears.

this is what i've got gathered up for the drive / power train. Looking for a nice street truck feel.

What do you think?

Also, any suggestions on an HEI distributor? (AC-R44 plugs)

2014 GMC Sierra All-Terrain Sonoma Red Crew
1956 GMC StepSide - in progress


Edited by regan56 on 06-13-17 07:10 AM. Reason for edit: No reason given.

 




acardon 
Ultra Senior Member
Posts: 11020
acardon
Loc: DFW TEXAS
Reg: 03-25-05
06-13-17 07:30 AM - Post#2695780    
    In response to regan56

With a 2.52 low and a 3.08 rear, it's not going to be very peppy on take off and a 750 carb is pretty large for a 327. A 700R4 has a a 1st gear of 3.06 and the OD would allow a 3.36 or more rear abd keep the cruising RPM down.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
regan56 
Very Senior Member
Posts: 1522
regan56
Loc: Regina SK Canada, eh!!
Reg: 12-09-02
06-13-17 08:37 AM - Post#2695795    
    In response to acardon

  • acardon Said:
With a 2.52 low and a 3.08 rear, it's not going to be very peppy on take off and a 750 carb is pretty large for a 327. A 700R4 has a a 1st gear of 3.06 and the OD would allow a 3.36 or more rear abd keep the cruising RPM down.


ya i had picked up the rear end for basically nothing without knowing what was inside, so when i checked it at home i was kinda thinking the same. The carb..again free but is it too large?

2014 GMC Sierra All-Terrain Sonoma Red Crew
1956 GMC StepSide - in progress


 
Impala65SS 
Valued Contributor
Posts: 4076
Impala65SS
Loc: Sweden
Reg: 08-23-07
06-13-17 01:43 PM - Post#2695820    
    In response to acardon

"Qjet" - It's a Rochester Quadrajet. The air valve and the array of fuel circuits designed cover so many part throttle conditions that no other carb can do, tells me it will work great - if the correct jets and needles can be found...

I have a low compression 327 in a 1970 c20. It's OK but I'm thinking about getting something with more torque (bigger), instead of trying to make a basically high revving engine behave as a truck engine.

I agree a th700 is a better match with the rear end.

There are those wanting a 327, rather than a 350 in Chevelles, Camaros and Novas, so I would consider selling the 327, then get at least a 350. A vortec 350 and find the best cam for your needs and the final gear you end up with.

A big body GM HEI is the way to go. An original GM, rather than the aftermarket. I hear the quality of aftermarkets are varying. The OEM works really well - even after many miles.

http://www.youtube.com/watch?v=SXn2QVipK2o&a mp;fea...


Edited by Impala65SS on 06-13-17 01:47 PM. Reason for edit: No reason given.

 
regan56 
Very Senior Member
Posts: 1522
regan56
Loc: Regina SK Canada, eh!!
Reg: 12-09-02
06-13-17 02:46 PM - Post#2695827    
    In response to Impala65SS

ya..i wont be selling the 327..i just finished rebuilding it. id be divorced.

teh TH350 i have needs to be looked at as i cant recall what condition it was in when i bought it a few years ago, so there is an option to be swapped out.

i guess i have two options

1. different geared rear end - 3.31/3.44/3.55 or whatever
2. different tranny - 700R4 say

2014 GMC Sierra All-Terrain Sonoma Red Crew
1956 GMC StepSide - in progress


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17178
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
06-13-17 05:16 PM - Post#2695842    
    In response to regan56

  • Quote:
The carb..again free but is it too large?


while a 2.87:1-3.08:1 rear gear if far from ideal for a performance application,and yes displacement does mater,as does the transmission gearing and/or converter stall speed, a great deal of the throttle response and the effect your carbs flow rate has on the torque curve,will be related too the cam timing, the engines compression ratio, the intake manifold design, and how your throttle is employed (IE an experienced driver can do a great deal to influence the way the car responds, an experienced driver that knows his cars characteristics can do a good deal to maximize acceleration.)yes you can improve acceleration with a higher numerically rear differential ratio like a 3.73:1-4.11:1 gear especially with an over drive transmission, and a 2600 rpm-3200 rpm stall converter, but its the driver who controls a good deal of the cars ability to put power effectively to the pavement. and the ability to match the cam timing, intake design and properly tune the combo you have is critical. a 327 has a fairly short stroke of 3.25" and that potentially allows it to be matched to high flow rate cylinder heads and a solid lifter cam that will allow the engine to operate in the 7000rpm plus range

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 06-13-17 05:37 PM. Reason for edit: No reason given.

 
models916 
Valued Contributor
Posts: 4781

Age: 67
Loc: Addison, IL
Reg: 05-28-10
06-14-17 07:01 AM - Post#2695898    
    In response to grumpyvette

I would go with a 3:40-3:70 rear gear with the OD.



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17178
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
06-14-17 07:16 AM - Post#2695901    
    In response to models916

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

all it takes is a tiny bit of research and some math to calculate the ideal rear differential gearing, tires size etc. and transmission gear ratios, and you can certainly select the correct torque converter stall speed if you have a dyno graph of your engines power curve without much difficulty, an hour or so spent in reading and research will provide you with a great deal better performance from most cars.
and a couple days worth of research and doing some math on all of the power trains component parts will provide you with a wealth of info that can prevent you from making costly mistakes.


IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
regan56 
Very Senior Member
Posts: 1522
regan56
Loc: Regina SK Canada, eh!!
Reg: 12-09-02
06-14-17 07:27 AM - Post#2695903    
    In response to grumpyvette

  • grumpyvette Said:
  • Quote:
The carb..again free but is it too large?


while a 2.87:1-3.08:1 rear gear if far from ideal for a performance application,and yes displacement does mater,as does the transmission gearing and/or converter stall speed, a great deal of the throttle response and the effect your carbs flow rate has on the torque curve,will be related too the cam timing, the engines compression ratio, the intake manifold design, and how your throttle is employed (IE an experienced driver can do a great deal to influence the way the car responds, an experienced driver that knows his cars characteristics can do a good deal to maximize acceleration.)yes you can improve acceleration with a higher numerically rear differential ratio like a 3.73:1-4.11:1 gear especially with an over drive transmission, and a 2600 rpm-3200 rpm stall converter, but its the driver who controls a good deal of the cars ability to put power effectively to the pavement. and the ability to match the cam timing, intake design and properly tune the combo you have is critical. a 327 has a fairly short stroke of 3.25" and that potentially allows it to be matched to high flow rate cylinder heads and a solid lifter cam that will allow the engine to operate in the 7000rpm plus range

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...



teh 327 has a stock intake and with heads from a 350. it ran like that before i got it and i wasn't game to change that part, maybe later if i feel the need.
i see alot of the responses i get are regarding performance (maybe partly because thats the forum i'm in) but i'm not looking for a hard shooter off the green lights that burns through all gears. i do want it to be able to handle itself and not take 3 seconds to take off from a dead stop though. i don't disagree that a different gear ratio and / or a different trans would be "better" but is it necessary?

maybe a street truck isnt the proper terminology then..think of it as a Saturday night cruiser that gets some daily use here and there, but isnt an old dog, but maybe a middle aged dog that knows some tricks but knows better than to show-off.

oh and i do know how to handle the throttle to make things do what i need.


2014 GMC Sierra All-Terrain Sonoma Red Crew
1956 GMC StepSide - in progress


 
regan56 
Very Senior Member
Posts: 1522
regan56
Loc: Regina SK Canada, eh!!
Reg: 12-09-02
10-25-17 10:51 AM - Post#2712119    
    In response to regan56

..well i took the TH350 to a trans shop for a quick review before i stuffed new parts back in it. pump is shot, case worn, sun shell worn/warped, all the frictions were wasted (that i already knew) long story short.,.its garbage. not the end of the world as it was a BOP trans that i got for basically free.

looking for a 700R4 now...

2014 GMC Sierra All-Terrain Sonoma Red Crew
1956 GMC StepSide - in progress


 
regan56 
Very Senior Member
Posts: 1522
regan56
Loc: Regina SK Canada, eh!!
Reg: 12-09-02
05-12-18 06:03 PM - Post#2733823    
    In response to regan56

Update..brought home a 700r4 from a 91 Chevy today. Should work much better with the gears I have in the backend. Thx to grumpy for the links.

2014 GMC Sierra All-Terrain Sonoma Red Crew
1956 GMC StepSide - in progress


 
greg_moreira 
Very Senior Member
Posts: 3274
greg_moreira
Reg: 10-06-03
06-03-18 09:05 PM - Post#2735859    
    In response to regan56

  • regan56 Said:
  • acardon Said:
With a 2.52 low and a 3.08 rear, it's not going to be very peppy on take off and a 750 carb is pretty large for a 327. A 700R4 has a a 1st gear of 3.06 and the OD would allow a 3.36 or more rear abd keep the cruising RPM down.


ya i had picked up the rear end for basically nothing without knowing what was inside, so when i checked it at home i was kinda thinking the same. The carb..again free but is it too large?



The carb is fine. Every 4 barrel Qjet made was 750 or 800 cfm and they were used on quite literally every division of vehicles from GM

Whether truck motors, car motors, many healthy factor engines, or an anemic 140 horsepower emissions era slug... it had at least a 750 cfm quadrajet on it.

Without knowing cam specs its hard to say for sure, but in general that sort of build with a moderate cam will be fine for cruising once dialed in.



 
Jims56chevy 
Frequent Contributor
Posts: 2421
Jims56chevy
Age: 64
Loc: chino valley az
Reg: 11-23-04
06-25-18 12:29 PM - Post#2738151    
    In response to regan56

700r4 and some 373 rear gears,you will like it.

56 210 2dr


 
carbking 
Senior Member
Posts: 1435
carbking
Loc: Missouri
Reg: 06-14-03
06-26-18 09:20 AM - Post#2738222    
    In response to Jims56chevy

The carb size will be fine. Without knowing WHICH Q-jet you have, cannot say this particular one will be fine.

If it came with the 350 heads, it will be fine. Even though it came from a 350 and you have a 327, calibrate it to factory specs. You now have a reasonable starting point PLUS a repeatable base-line.

Depending on the camshaft, it might be necessary to change the vacuum piston spring. If idle vacuum is 14 or more, changing the spring will not be necessary.

Get the Q-Jet book written by Cliff Ruggles. Read it cover to cover. Done correctly, VERY difficult to improve on the Q-jet for a moderate street engine.

If the carb did NOT come with the 350 heads and intake, post the number. Yes, MOST Q-jets were either 750 or 800 (and the scarce 850) CFM, but the original calibrations will be easier to work with if you have one from a 350 Chevy rather than say a 500 Cadillac. Both 750 CFM, but calibrations totally different. Why buy additional parts if you can start with the correct calibration?

Jon.

Good carburetion is fuelish hot air!

The most expensive carburetor you will ever buy.....is the incorrect one you attempt to modify!

If you truly believe "one size fits all", trying walking a mile in your spouse's shoes!


 




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