code 23 gives 3:54 on some sites

4750 lbs is what is written on the regis !
the gvwr is 8100 lbs

 

The 4750 sounds right for an empty cargo van before the conversion was done--I believe my older vans had a registration weight as it left the factory. I would guess you're carrying around 5500+ lbs if you have any significant interior trim work, seating, subfloors and side panels, cupboards, etc. Is it a factory conversion or homemade? Raised roof? Then add people and luggage and you're pulling around 3 tons.

In any case, you want trucklike grunt, not high rpm power, so huge intake/exhaust stuff is not what you need.

I'm seeing 3.54 on a quick lookup for code 23. That is better than the 3.42 I changed my '86 GMC to from the stock 2.73. If you had a 3 or 3.25 I would push harder for a ratio change. Definitely a 3.73 would be great but would it be worth the money? 4.10 is getting extreme and prolly would hurt your gas mileage. Hey do you have stock size tires or taller?

I'd just get the engine running well and drive it. Remember the old VW buses from the 50's started with 36 horsepower...

George

 

Ahh No. There is an easy 50-75hp and even more torque to be gained with exhaust and a cam on this vintage motor, that is how restrictive the stock parts are. The stock heads are a bottleneck above 4000rpm on this displacement too so there is no danger of making a screamer out of it, but any improvements in airflow will produce torque and fuel milage gains. You're gonna have to trust me here.. any experience you may have with a chevy of the same vintage simply does not apply.

 

I'll defer to Konanski on the engine mods. I'm guessing the cam grind you'd want is the "truck/rv" thing that makes more power low down. If the heads choke the engine above 4 grand, the exhaust would have to be really restrictive. Can you put 460 exhaust pipes and mufflers on the van if they happen to be bigger?

Cam changes are more feasible for good old pushrod engines because there's only one of them

George

 

The exhaust needs to be matched to the package
too big of a system will hurt performance

 

+1, in this case that means a 2.5" Y into a single 3" cat back system would be about perfect, big enough not to limit HP potential at higher rpms but small enough to still provide good scavenging at low rpms for good torque production. Using a hydraulic pipe bender typically found in a muffler shop the 2.5" tube gets reduced to about 2-1/4" and same thing happens with the 3" as it bends up over the rear axle, but combined with any aftermarket cat and muffler you can buy this system will easily outflow the stock setup especially if headers(even shorties) are used.

 

whats the budget , more horses more hay.

 

Been modifying engines for 35 years


But I`m looking at E-250 experience here ,




I dont mind putting a crane 444232 like said somewhere & duals


but if I gain 2 mpg and 20 ftpds of torque ...it`s worthless !


is the CR really 8.8 to 1 ?


changing the heads is not in my plans for now
and not the type of rig that I would rev past 4000 rpms unless on kickdown


this is a leisure van,,,,,,just want to gain performance/economy


this van is soooo slugish ............. ( totally stock with cats + air pump )


thanks
Dan

 

If you knew what you were doing you wouldn't ask that type of question.
35x0 = 0

 

I guess ill have to rely on you then !

 

I don't come cheap. You pay for expenses and my time , I'll do it .
Conaski told you what to do. There are no cheap, quick fixes on a engine from this era.

 

If you dont want to change the heads all else is pointless. 30 year old cast iron smog heads will not make power at any rpm .

there are two reasons modern motors make great power EFI and modern head design !

A top end kit from edelbrock is a proven gain if one stop shopping is your thing.

 

would 1970 4V heads fit direct on the MPFI engine ?

what should be the CR with these ?
or maybe it`s not worth it ?

 

the C.R for a truck should stay below 9 with aluminium heads you can bump a half a point.
I cant stress enough that the ONLY way to make power is with better heads.

the problem is that the fuel injection of your van is hard to tune to any modifications that you make.

Without a budget all advice is pissing into the wind . to make any real power out of this era
the whole top end has to be replaced with a matching cam ,then the choice is going to a carb or finding a tuner who deals with this era ecu. good luck

 

Does this thing have a c6? Changing to a E4OD would likely solve your problem. My old 88 e350 utility body had a 351w c6 and 410s sitting around 7-8k. I didn't think it was that bad it sure wasn't fast though. My 95 e250 w/351w e4od and I want to say somewhere in the mid 3s rear. It feels like a race car compared to driving the 88. The weight helps a lot im sure but I've heard the c6 trans robs 60 horse right from the motor.