Want to swap a 305 for a..?

[TheBumbleBeeTruck]

I'm new here, and looking for some advice. I'm 16, and got my first truck, a 1985 chevy 3/4 ton stepside, yellow with black fenders, and an orange flashing light behind the cab. Called the BumbleBee truck. I'ts an ex county truck

It's got a 305 in it right now, which really has no power. It struggles just going up hills, and's just plain not powerful. I'm also a boat guy, (since you can run boats when you're 13, I got 4 boats right now.) I'm pretty sure that it wouldn't make it up a hill with a 3000-3500 pound boat.

Well, I went for a ride again in my buddy's 1985 dodge 1/2 ton, that he put a 440 in. That thing really moves, even though he says it only has about 300 hp. That really made me want to look into some crate engines.

So, I'm really new to all this, and was lookin' for some opinions on what the best engine is. So I'm looking for a 350, or maybe a 383, but I want to try and keep the price around $3500, so I'm guessing that kinda limits me to 350, or a 355? But can spend more if need be. Looking for turn key, or almost turnkey preferably. I was hoping to get something around 300 to maybe 375 hp, I looking for something with good torque, because I need to be able to tow boats with it, but also like to hotrod around with it a little bit, (remember I'm 16.)

The transmission in the truck from what I can tell is a 700r4, at least I know it's a 4 speed automatic. Will an engine like i'm talking about bolt up to that tranny, will put to much stress on it?

Any advice/ knowledge like best brands, best place to buy (I've been looking on Jegs mostly so far) etc is most appreciated. I really don't know a whole lot but would really like to learn.


Thanks

Logan

[Boone83K10]

Welcome. Pretty cool to have a 3/4 ton stepside. As far as engine wise, you could get the GM crate 350 that has 290 hp/ 326 ft lb. Theyre way under your budget, but always good to have some dough. The 700r4 will bolt up to just about anything. The main enemy for a 700r4 is heat and improper tv adjustment. Being that it was a county truck, you can assume it was thrashed on by the workers but probably had good maintenance. With that in mind, maybe use the extra dough for a trans rebuild. You can use any site really, but I like summit racing better than jegs.

 

[rich weyand]

I have been all over the 350 cam thing over the past two years.

The problem with the GM 350/290 crate engine (GM #12499529) is that it does not have the low end torque you need.  GM put the cam from a high-compression 1967 Corvette engine in a low-compression 350, and it has low static compression and a lot of overlap.  What this gets you is horsepower up top, but no bottom end.  BTDT.  With this engine my truck was a slug off the line, though it was a two-lane terror for passing.  50-90 mph times were excellent.  0-50 times were l-o-n-g.  Particularly in a truck, this is a bad choice.  This is also an old-tech cam grind.  Modern computer-modeled cams deliver much better performance for the same givens.

The better choice is to get the base GM 350/260 crate engine (GM #10067353), save yourself about $500 compared to the 350/290, and then swap the Comp Cams 12-235-2 cam into that engine before you even put it in.  I swapped out the cam in my 350/290 once it had been in the truck a year, and it's a LOT more work to swap a cam after the engine is in the truck!  This cam is a modern grind, will give you 300 hp, but will also give you almost 400 lbft of torque, with almost 300 lbft at 1000 rpm.  Which means it will have grunt from the get-go, for getting off the line as well as for pulling those boats.  Get too pedal-crazy with those numbers and you will get to know the people at your local tire store really, really well.

If you swap the cam into the new engine, you'll void the warranty, but them's the breaks.  You also don't need to change out the lifters (which set up to the cam within the first hour of operation -- once the engine is run AT ALL, if you change the cam, you MUST change the lifters) or the springs (as the stock springs in the 350/260 engine will work fine with the 12-235-2 cam).

Now engine alone isn't enough.  You also need all the right plumbing to get those numbers. I would recommend an Edelbrock Performer intake manifold, a Quadrajet tuned to order by Sean Murphy Induction, Hooker headers, and dual 2.25" exhaust through a pair of Flowmaster 40 (louder) or 50 (quieter) mufflers, with a 2" H-pipe.

You can probably pull off that whole setup for the money you're talking, and have some real nice performance cheap.

There are other ways to go, but you can get into big money pretty fast with engines.  And most concentrate on high-end horsepower (great for the track), at the expense of low-end torque (better for the road).  Given that it's a truck, and you are looking at towing as well, it's hard to beat the above setup for the bucks.

[hobbz]

Rich, would that combo be 87 octane friendly?

[rich weyand]

With those stock 76cc low-compression heads (8.5:1 advertised, probably more like 8:1 in reality), it'll run on dog urine.  I have the base timing set at 16* BTDC, with the stock 20* centrifugal and 15* vacuum advance, and it never pings, ever, no matter kind of pump gas I put in it.  Bottom of the barrel around here is 87 octane, and that's all I run, the cheaper the better.

There are four cams to look at: 12-300-4, 12-231-2, 12-235-2, and 12-238-2.  In the order I just gave, they are: 1) increasing in lift (harder on the valvetrain); increasing in horsepower; decreasing in bottom-end torque.  Now all four of these are torguer cams, so they all have a lot of torque that comes on early, but 12-300-4 (which I have) is the gruntiest, and 12-238-2 (which nlauffer on this board is using) has the higher horsepower up top.  The 12-235-2 is probably the best choice for day-to-day driving, while the 12-231-2 is probably better for occasional towing.  With any of these cams, you can run the stock-spec torque converter, which takes strain off the tranny compared to a higher-rpm torque converter, especially when towing.

You can run all of these on the Camquest software download (just google Camquest) and see what I am talking about.  Put in the 350 SBC numbers, and the plumbing description (headers, etc) and you can compare the cams.

[TheBumbleBeeTruck]

Thanks for the input! I'm looking at a crate engine that has been sitting in a shop of a friend of friend of mines dads. It's a crate 350, never run which he says has 350 hp. It looks just like the 260 hp in the picture you see on SR or Jegs. I'm guessing that's what it is? But it's 700 bucks. If it is a 260, I could do just what you said, but what if I wanted it to make around 350 horsepower? Could I put some different heads on there, if so, which ones?

Thanks

Logan

[rich weyand]

GM has a 350hp 350cid crate engine.  If that's really what this is, just leave it.  Look it up on Summit.

[TheBumbleBeeTruck]

I couldn't seem to find one. Can you find a link, maybe I'm just really bad at navigating those sights. The only reason I'm asking is because it looked just the same as this

http://www.jegs.com/i/GM+Performance/809/10067353/10002/-1?CAWELAID=1710611204&catargetid=230006180000109933&cadevice=c&&cagpspn=pla&gclid=CLr5taDVnbsCFc9sfgodYmIA0A

Thanks

Logan

[rich weyand]

Every SBC pretty much looks the same.  You can spot head differences, if you know what you're looking for, but cam, rods, pistons, crank differences are not apparent from the outside.

A 350 hp 350 cid won't be running the 76cc heads.  So one thing to do is get the casting number off the heads and tell us what that is.  Someone here will know which heads they are.

Here's the Chevy 350/350.  Note it has later-model Vortec heads (64cc, 9.1:1 static CR) not the earlier 76cc heads (8.5:1 static CR).
http://www.jegs.com/p/Chevrolet-Performance/Chevrolet-Performance-350ci-350HP-Circle-Track-Factory-Stock-Engine/752396/10002/-1

[TheBumbleBeeTruck]

Right, would they make the higher Hp without the chrome timing chain cover, or valve covers?  It seems like all the higher HP motors have that, but remeber this engine is 5 years old, would that make a difference?

I found a number for heads on a 260hp on the internet. Waiting for the guy to call me back, then I'll ask him what the number is.

Thanks for the link.

Logan

[Stewart G Griffin]

My .02 cents for a 16yr old, would be to try headers and a decent exhaust first.

Also, what is your diff gear ratio?

[Stewart G Griffin]

P.S.   Remember, i turned a 17.9 sec quarter mile with a 305.  i agree, this is not fast, but i have 2.56  diff gear.

i'm just trying to say that a 305 is not as handicapped as you might think.

[dvdswan]

Also, what is your diff gear ratio?

I would suspect this first, Rich is right on on the engine choice but if you have a high gear set, you still won't have good pulling power.  for towing you should have 3.73 or even better 4.11 IMO (with stock to 31s).  if you have those, then go for the engine stated by Rich.

[Engineer]

Chevy offers a high torque 383.

Nasty:

http://www.chevrolet.com/performance/crate-engines/small-block-ht-383.html

http://www.hotrod.com/techarticles/engine/gm_ht383_crate_small_block_tune_up/viewall.html