[Augusto]

My C30 dually has a 350 stock except for a pair of heads off a 267cid, I installed them despite the small valves because I live at 6.600 feet of altitude and the extra CR is very welcome, it performs nice on regular gas, but since I use this truck to haul about 7.000 pounds, I would like to get more torque out of the motor, I have an Edelbrock Torquer II manifold laying around, how would this engine perform with it? I also have a 0-1850 600 cfm holley to complement, the truck has 4.56 rear end and a TH400 tranny, dual 7.50 x 16 tires, the motor very seldom sees revs above 4.000 and the throttle goes WOT going uphill fully loaded in 2nd gear.
please make sugestions to improve it.
thanks,
Augusto.

 

[onovakind67]

What kind of intake manifold is on your truck now? What kind of carb?

Up to 4000 rpm it's really hard to beat the small runners of a stock intake manifold. What does your exhaust system consist of?

 

[curtis73]

I agree. At your altitude, skip the four barrel and do a nice 2-barrel. If it truly never sees more than 4000, 600 cfm is about twice what you need and it will hurt torque. Just for the sake of comparison, a 350 at 4000 rpm and 80% VE needs 324 CFM. A nice 2-barrel holley or 2jet will provide you with 390 which is still more than you need

Think velocity. There is obviously a point that is too small, but small intake runners, head ports, and carb will keep that intake velocity up which will help torque by improving cylinder filling capacity. Also think about small tube full length headers, a dual 1.75" exhaust with (possibly) an H-pipe crossover. I say possibly because its about $40 more at the muffler shop, but it will help even out exhaust pulses in such a small exhaust and help torque.

Consider something, though. With 4.56s and tall tires you might want to take advantage of a little more RPM from that 350. You have a ways to go up in power before you start shifting your torque curve up in RPM.

 

[rreruption]

If you're talking about a rebuild.Put a 400 crank in that motor.Making it a 383.Id try to keep the compression around 9:1-9.5:1.Use a comp 4x4 cam or something like a 256H xtreme energy cam.If your towing you will want to stay on the low end with cams.The only problem I see with 267 heads is.The intake valves are probably a 1.84.I would personally use other heads.Vortecs are good street heads,you'll need a diffferent intake if you go that route.Dart 165cc are also good heads.there are plenty of good heads that will work better with youre application.If you afford it roller rockers are also a nice touch on any engine to reduce some friction and free up some power.On the intake I'd pass on the torquer 2.Those intakes build power from 2500 and up.Get a regular good old performer.A 600cfm holley is plenty of carb,and a good choice.I dont know if youre running headers,But it would sure help.
If rebuilding it as a 383 is to much.I would put money in better heads,Roller rockers,a better cam(Make sure you at least get a good double roller timing chain),Headers,Performer intake,and 600cfm holley.
Also 4.56 gears might be a little steep for a 350.Go with lighter gears like a 4.10 or 3.73.

 

[SuperDeluxe]

Its simple, supercharge it. Your at 6,000+ feet? Yeaaaaaa, put the extra lung on it.

 

[DoubleVision]

add a edelbrock performer plus camshaft or the summit cam of the same specs, a new double roller timing chain while your in there, tune it up with the best pieces you can get, spiral core spark plug wires, brass terminal cap, etc. A K&N Airfilter. I would not use the torker intake, it has a open plenum which is the opposite way you want to go, if the truck has a Quadrajet on it, stick with it, as the small primary`s of the Q-jet make for outstanding low end response, add a edelbrock performer intake to go with it, and this whole combo will give your truck alot more pulling power as well as mileage.

 

[454C10]

Headers and dual 2.25 inch exhaust would help a lot. I would use a set of dynomax mufflers. Quiet but flow well.

The stock intake makes loads of torque under 3500 rpms. I wouldn't use a torque II intake for your application. Torquer is just the name they gave it. It doesn't mean that is makes torque (strange but true).

A compcam 252H would be a good choice. And it will work well with the stock valve train.

If you have the money then change the heads. Get a set with under 170cc on the intake port. AFR, edelbrock, dart iron eagle, all make good small port heads.

Of course, a 383 kit or a complete 400 would help a bunch. But you already knew that!

 

[Bumpstick]

Ditch the mouse and go with the RAT...!

Augusto... Follow your feeling use the force of the RAT... (StarWars effect here...)

 

[PapaWrench]

I agree with bonzaipenguins on the 383. If you're really "hungry" for torque, get a cummins turbo diesel, but you better have a drive train to back it up.

 

[killerformula]

A high-torque motor is pretty easy to build. To be honest, it sounds like you could use a chunk more horsepower too, so maybe the new build that others are suggesting is really the way to go. Just a quick note: Torque is the amount of work you can do. IF you're getting up the hill (force over distance) you're doing the "work." Power is how fast you can do work. If you want to get up the hill faster, you'll need more power too (work/time). Most diesel trucks used to crank out about 150 horse and about 600 Ft/lbs of torque. They'd be over in the right lane with their blinkers on in the 60's and 70's spewing black smoke going 35MPH up a hill. Nowadays you've got turbo diesel mills that put out a bit more torque, but are producing something on the order of 500 horsepower to boot! If you're pulling 4 tons regularly, you really do need a different setup. In order to make suggestions I think we need to know how far you're willing to go to change this situation and what you're willing to spend.

K

 

[SuperDeluxe]

I don't understand, 98% of diesel trucks on the road today use a turbocharger, back in the day they used either a supercharger or a combination of supercharger and turbocharger. This guy is above 6,000 feet, the air is thiner, less dense, which makes a small 144 Holley or Wieand supercharger perfect for this guy if he is willing to switch back over to larger combustion chamber heads with some seats and valves capable of taking the heat he is going to dish out holding the thing wide open ascending the hill. Forget all this stroker garbage unless your already running a 502 in your truck which you are not right now. Swap those heads out, buy the blower kit and you will never be able to wipe the smirk off you face again. :thumbup:

 

[Augusto]

I'm in a big dilema, I have a B&M 144 blower but is going on top of a built 350 for my El Camino, I also have a 454 ( rats are great!! ) but it's destined to power my '46 chevy fleetmaster, I use the truck for work and need more power when going up the twisty roads we have over here, I've been thinking about turbocharging it ( I've done this several times before to jap 4 bangers ) the motor has the stock manifold, the 800 cfm q-jet from the 454 (this is the motor that came originally in the truck but I swaped a 350 instead just to get the rat for my '46 and I'm not going back ) and has the stock iron manifolds dumping into 2 1/2 dual pipes exiting ahead of the rear tires with turbo muflers. Originally I used the 2 barrel intake and carb from the 267 it was a dualjet, performed well but the q-jet it has now works better, in this case the big carb was an advantage, I also have a set of 305 heads, do you guys think they will work better than the 267's? I can't afford buying aluminum heads, if I could I'll buy them for the 454.
Please add your thoughts.
Augusto.

 

[killerformula]

I don't understand, 98% of diesel trucks on the road today use a turbocharger, back in the day they used either a supercharger or a combination of supercharger and turbocharger. This guy is above 6,000 feet, the air is thiner, less dense, which makes a small 144 Holley or Wieand supercharger perfect for this guy if he is willing to switch back over to larger combustion chamber heads with some seats and valves capable of taking the heat he is going to dish out holding the thing wide open ascending the hill. Forget all this stroker garbage unless your already running a 502 in your truck which you are not right now. Swap those heads out, buy the blower kit and you will never be able to wipe the smirk off you face again. :thumbup:

Not a bad idea, but an expensive one to be sure. The blower itself will be pretty pricey, and I don't think the motor he's got is really built to support one. He'd need a nicer set of slugs, a blower-ready carb, a blower cam and different heads probably because the 267 heads he has would be too much compression (and their performance ability is so low it sort-of defeats the purpose of going through all the trouble of having a blower- although blowers are less "head dependent" than N/A motors). On top of that you'd probably be stuck running premium gas from now on, and you'd have a 5,000 dollar investment into "getting up hills better."

You could probably find an early-90's 454 roller motor at a junkyard for 5-600 bucks. Hone out the bores, freshen it up and drop it in. probably 1200 dollars later you've got all the towing power you'll ever need... on regular gas!

K

 

[Augusto]

man we don't have junkyards as known in USA, most vehicles here run until they vaporize because of rust, it's very hard finding parts from totaled cars, but rats, no way most people don't even know what they are, our streets are flooded with japanese stuff, 4 bangers rule here and I belive they really suck, people is bitten by the "tunnin" wave wich I find obnoxius and offensive, fake carbon fiber shift knobs, 20 in rims, tires that seem deflated, and plastic aluminun/diamond plate floor mats and they think they have a great ride, it really sucks man I'm tellin' you.
Can't wait 'til I build my '46 chevy with the rat motor, they won't be able to see them toyotas in the smoke of my hides, I already installed a complete chassis off a C10 under it, and had driven it with the blown 350 but I want "more power" (I love Tim Allen's philosophy).
But my truck is still slow, I saw a Mercedes 355 turbo diesel from a dump truck the other day and been thinking if the TH400 could be fitted, it was expensive though, they asked $3.500 not sure if it's worth going that way, it would be awsome though. I'm off to buy the lotto rigth now, there is a 2 millon prize this week.... now I'm drooling, thanks to everybody for your help.
Saludos from the middle of the world.
Augusto.

 

[JAKE 68 GMC]

You could bolt on 882 SBC heads. They wouldn't be as good as a Vortec or aftermarket head, but they would be cheap, and way ahead of 267 heads. Just my $.02

 

[story]

if you want more torque and power on somewhat of a budget get some cast iron world motown heads with a 64cc chambers an okay set of roller rockers a comp cams 4x4 cam with around 470-490 max lift and under 215 duration for intake and 218 for exhaust about a 600cfm holley and a weiand stealth intake(its a damn good intake :thumbup: ) that will give you a powerband from off idle to about 6500 and a very noticable increase

 

[SuperDeluxe]

You can also try a 472 or 500 Cadillac.