I bought a camper special from the family of the origional owner.
It's got the 350 4v and the close ratio NP 435 4-speed.It's got the
heavy duty springs ,373 Dana gears etc.
I had a rebuilt motor put in but am not happy with the
power.Apparently they lowered the compression from the stock 9-1 to
somewhere below 8-1 (feels like 7.5-1)
Anyway,I just came into some bucks and I was thinking about getting a
travel trailer (maybe 27 ft.or so) and maybe even getting a better motor
so I wouldn't be a traffic hazzard trying to pull the thing in the
I've read about a 388 "stroker" ,that is a 350 block with a 400 crank.
Anybody have any idea if this engine would have the power to pull
6-7000 lbs. through the Western mountains without too much trouble?
I would not call the NP435 a close ratio tranny by any means. If it is a
close ratio tranny, it is not a NP435. The stock 4 sp that year was a
SM465 with is a very tuff tranny with a granny gear also and still
"prized" today. A couple of things here. First your gears are too tall
for that weight and terrain. You are looking at a 4.10 to 4.56 here. If
you want too serious increase engine power I would not waste time and
expense with a 383. I would look for a 454 and bolt it in because that
engine will perform better tow and at altitude than any 383 will and you
might even still get by with your 3.73's with a 454 under the hood. A
big block would play well and fit easily in that old truck.
For any engine to have power it has to be built right. Induction, heads,
cam, and exhaust is where the true power comes from in an engine. The kind
of $$$$ you want to spend will have some baring on how much power you will
get. You already have one of the most solid power building engines ever
made! If you want to build it into a stroker, be very careful what
combination you go with. 400 rods are typical but are harder on cylinder
walls and make for a narrow powerband, 350 rods are a great balance between
power and cost. There is also non-factory rod lengths available. Cam
selection is vital to making great power where you need it, but a stout cam
in a 350 will be toned down in a stroker.
377=stock 350 bore(3.48) with a 400 crank(3.75) with downsized main journals
383=.030(3.51) oversized 350 bore and 400 crank.
388=.060(3.54) oversized 350 bore and 400 crank - AVOID this big of a bore
in a stock block at ALL cost. Typically hard to cool and very prone to
cracks in cylinder walls.
A GMPerformance Ram Jet 350 is an AWESOME engine for the money. Fuel
injection, warrantee, brand new everything(no reconditioned or rebuilt
GMPerformance also sells a 383, also brand new, but I think its more for hi
performance than highway towing.
I would consider working on what you have. Did they install dish
pistons? Did they install a milder than original cam? An Edelbrock performer
intake, 600 performer carb, SR Torquer heads(67cc for dished pistons - 76cc
for flat tops), maybe a Crane Energizer 266 or 272 cam or a comp cams Xtreme
4x4 cam. A setup like this with a great set of headers and a 3inch single
exhaust system would give you plenty of pulling power. A strong Hays
Borg&Beck performance clutch kit would probably be a good idea for holding
power and longevity.
There are SO many ways to go. What way do you wanna go?
BRAIN FART!!! Sorry... I was quoting the stock 350 crank size instead of
bore size... I corrected myself below... Don't ask me what was going through
my head. I don't think anything was besides air! Please forgive my oops.
The problem with this long post is that what work good for racing or
sporty driving and what work for towing is two different matters plus
what works at sealevel does not work at 6 or 8000 feet towing up a hill.
You want more than a 350 or 383 if your goal is good high altitude
towing performance. I have been there and one that and for high mountain
towing you want deep gears and a big engine because of power loss as
altitude goes up.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.