350 Crate Engine & more questions!

[1970CustomCamper]

First post.
I have a 70 GMC Custom Camper 3/4 ton with a 225 hp stock 350 engine and 350TH tranny. The truck has 69,000 original miles on it. Other than duel flowmaster exhaust it is stock. I bought it 6 months ago, and I love it. It is my daily driver and I work it pretty hard because I tow my work trailer behind it daily. The trailer is 1 ton dry and usually 2-3 tons full.
Problems- It runs hot. Has a clogged radiator. It leaks oil from everywhere. Has compressions of 140, 110, 90, 140, 120, 95, 130 and 140 in the cylinders. The plugs show corrosion (probably head gasket or cracked block). Factory AC doesn't work. Q-jet Carb needs to be rebuilt or thrown away.
Other than that it is great! LOL
I bought a whole bunch of goodies from Summit the other day with intentions of bolting them on to the existing engine. Gaskets, EDL valve covers, EDL intake manifold, EDL carb, EDL air cleaner, plugs, wires, dist. cap, aluminum radiator, water pump, 180 deg thermostat, water neck, timing chain and cover etc.
Now I'm debating a new crate 350 to bolt the goodies onto instead. I could buy a engine stand and build up a motor to drop in and replace the old.
1. 350 w/ 250 hp and 350 ft/lbs torque at 3600 RPM? -OR-
2. 350 w/ 290 hp and 326 ft/lbs torque at 3750 RPM?
3. Remove factory AC? Is this taboo? I don't really need it here.
4. Do I need to upgrade my transmission?
Price is an issue.
Advice is welcome. Help a brother out.
I'm in Southern Cal.
Dan

[smbrouss70]

First of all

Originally Posted by 1970CustomCamper

1. 350 w/ 250 hp and 350 ft/lbs torque at 3600 RPM? -OR-
2. 350 w/ 290 hp and 326 ft/lbs torque at 3750 RPM?

I would go with the 250HP and 350 ft/lbs torque version, I would think that you would want the version with more torque if you are using it as a work truck. The 250hp is also a little cheaper since you are trying to keep cost down. Also you get a pretty good warranty with the crate engine versus rebuilding what you already have, not to mention alot less down time since you are using it everyday.

Originally Posted by 1970CustomCamper

3. Remove factory AC? Is this taboo? I don't really need it here.

That's a personal call to me, I would leave it there just in case I wanted to fix it later. You do know that we have this Global Warming going on, right? It'll be 200° everyday before long.

Originally Posted by 1970CustomCamper

4. Do I need to upgrade my transmission?

If your transmission doesn't need a rebuild or anything, I would leave it there. TH350's are good transmissions for what you are doing. You could put a built 700-r4 or a 4l80E for the weight you are wanting to pull everyday and fuel mileage, but there goes the whole cost-conscience thing.

I'm definately not an expert on any of this, but it's my opinion, so take it for what it's worth.

[Jim_PA]

#1 for heavy towing, and keep the q-jet!!!

The 290 horse seems to be over-cammed for an otherwise stock engine.

[PanelDeland]

Welcome!! The thing to remember is Jim made a good point about the 290 HP and looking at the figures you gave the torque peak is at a higher rpm.If you are doing lots of towing the lower the torque peak the better it will usually tow.You may want to look into a crate 383 if you can.It need not be an all forged rotating assembly or have the bling factor of big numbers but the extra cubes and stroke will give you better torque.If you shop for one it may be close in price to the 350's you've been looking at.

[jsbgump]

Originally Posted by smbrouss70

First of all


I would go with the 250HP and 350 ft/lbs torque version, I would think that you would want the version with more torque if you are using it as a work truck. The 250hp is also a little cheaper since you are trying to keep cost down. Also you get a pretty good warranty with the crate engine versus rebuilding what you already have, not to mention alot less down time since you are using it everyday.


That's a personal call to me, I would leave it there just in case I wanted to fix it later. You do know that we have this Global Warming going on, right? It'll be 200° everyday before long.


If your transmission doesn't need a rebuild or anything, I would leave it there. TH350's are good transmissions for what you are doing. You could put a built 700-r4 or a 4l80E for the weight you are wanting to pull everyday and fuel mileage, but there goes the whole cost-conscience thing.

I'm definately not an expert on any of this, but it's my opinion, so take it for what it's worth.

[Moneypit]

Originally Posted by smbrouss70

First of all


I would go with the 250HP and 350 ft/lbs torque version, I would think that you would want the version with more torque if you are using it as a work truck. The 250hp is also a little cheaper since you are trying to keep cost down. Also you get a pretty good warranty with the crate engine versus rebuilding what you already have, not to mention alot less down time since you are using it everyday.


That's a personal call to me, I would leave it there just in case I wanted to fix it later. You do know that we have this Global Warming going on, right? It'll be 200° everyday before long.


If your transmission doesn't need a rebuild or anything, I would leave it there. TH350's are good transmissions for what you are doing. You could put a built 700-r4 or a 4l80E for the weight you are wanting to pull everyday and fuel mileage, but there goes the whole cost-conscience thing.

I'm definately not an expert on any of this, but it's my opinion, so take it for what it's worth.

X2

Oh, and

[1970CustomCamper]

Thank you guys for the input. I think I like the 250hp engine because of the torque. I also like the $1400 price tag. The 383 would be nice, but the prices I keep seeing are double the 350 engines. My plan was to use the Edelbrock square bore 1405 carb with the Edelbrock Performer EPS 2701 intake manifold for more performance. Someone recommended I keep the Q-jet? Also, I was reading somewhere that it might be a good idea to put a RV cam in it? Not exactly sure what that is, how much they cost, or where to find one?
Thank you guys for your responses. I'm learning a lot!
Dan

[byrd]

Q-jets are know fuel mizers, and work great when rebuilt and tuned properly, and generally hold their tune pretty well. Unless you are trying to get more power opr bling by using the edle intake and carb, the stock intake and Q-jet will be just a good and better on fuel.The stock intakes has small primarys but huge secondarys giving it better everyday fuel comsumption and great response and plenty of power when you open the secondaries, just my .02.

[Jim_PA]

Originally Posted by 1970CustomCamper

Thank you guys for the input. I think I like the 250hp engine because of the torque. I also like the $1400 price tag. The 383 would be nice, but the prices I keep seeing are double the 350 engines. My plan was to use the Edelbrock square bore 1405 carb with the Edelbrock Performer EPS 2701 intake manifold for more performance. Someone recommended I keep the Q-jet? Also, I was reading somewhere that it might be a good idea to put a RV cam in it? Not exactly sure what that is, how much they cost, or where to find one?
Thank you guys for your responses. I'm learning a lot!
Dan

I'd be willing to bet the 250 horse 350 has what most would call an RV/towing cam already in it. I would get a regular Performer intake (there are plenty around used) and have someone who knows what they are doing re-build your Qjet.

[CrashEd]

If it wasnt so far i could fix you up with a 402 bigblock and 400TH out of a 70customcamper/20 lots of towing power with that.
Ed

[jkeady]

Like Jim_PA said, I'd bet that if you compared the specs on the crate motor cam's grind with that of a typical "RV cam", they won't be far off. That's where you're getting that low torque peak from.

As for the carb, if you already have the Edelbrock, I'd go ahead and put it on with the Performer intake.

[GREASEMONKEY72]

where at in so cal are you?


i agree with whats been said above, youve got some good info there, and like said if you already have the eddy carb and intake go ahead and put them on but the qjets are known for good mpg and good power at the same time

oh and how bout some pictures of the truck???

[72lb4x4]

I'm no expert, but maybe a set of vortec style heads would be a good idea if not included with the motors mentioned. The vortecs are supposed to be the better setup these days

I've also seen opinions (and opinions the other way) on the internet saying that GM crate engines are overrated. Maybe pick up a .030 over short block locally, add vortec heads, cam, etc. of your choice and get a good running motor for "cheap." Then again, there's a fair amount of work involved.

Generally, bigger isn't better except for cubes if you don't care about mileage. The bits need to be matched to get the perf/mileage promised.