Motor Mounts on '86 Truck/Sub/Blazer

There are intake manifolds, headers, cams, and heads that will make great low end torque using your existing block. While most publications these days ignore lower RPM usage, that does not mean the parts are not there.

Just for kicks try contacting the people at Crane Cams and Comp Cams. Tell them your combination of parts and let them make suggestions to you.

You might also try some software like desktop dyno that will allow you to get an idea of how selected parts will make power. Even simple stuff like a cam change, and torque converter can make a HUGE difference. This stuff is often over looked by people. They slap together a power train combo then wonder why there drag car is running 3 seconds slower then they think it should. Or they wonder why there truck has torque at 3,500 RPM and higher, yet very little below 2,000 RPM. Charles

It has to do with rod/stroke length and angularity too. Long stoke engines can be made to have great low RPM torque.

----------------- TheSnoMan.com

Well, those "big-block" V6's would be TOO different. I need something that was at least offered in the same time period and same type of truck--for legal reasons.

I do like the idea though, and it'd certainly be cool in the right project truck. Seems like they'd be hard to find parts for though. You rarely even hear about them. I personally didn't even know of their existence until a few months ago.

~jp

SnoMan wrote:

True... although there do seem to be a lot less aftermarket parts available for L6's compared to V8's.

A while back I did venture onto one of the cam companies' websites, and did see a variety of cam profiles for the 250 and 292 engines. I do plan on checking into that once I have parts to work with on an engine stand...

I found someone selling it online for download only. Cheap too, like $12 or something. I plan on getting a copy of Desktop Dyno.

That comment about the 3500rpm truck engine hits a little too close to home ;-)

~jp

They where made up until the late 70's and possibly later. They even made a diesel version of same engine/block as well which tells you how sturdy the design was. I am not sure if it started life as a gas motor or a diesel but it was availble in both forms.

----------------- TheSnoMan.com

Both Comp & Crane cams can or will do a custom grind cam shaft for you. You just need to talk to the tech support at one of them to find out what you would need.

I would start with different cam in your current engine. Maybe a different torque converter. With a automatic torque converter size & stall speed makes a Big difference. You need to match the stall speed with the Cam.

Something else to remember, most of the 1 ton trucks that had 292 L6's had a numerically higher gear ratio. Often dual real wheel trucks were as high as 4.56:1 ratio. Charles

Those large displacement V6 & Super Large Displacement V8's were Medium Duty and Heavy Duty truck engines. Used from the mid 50's to the 70's. In the Chevy and GMC trucks the V6's were ONLY used in Semi-Cab Over Engine, or Full Cab Over Engine trucks. Trucks using the conventional modified pick up cabs did not have the room under the hood for them. Those trucks from 1958 to 1965 either a 265, 283, or 327 C.I.D. Small Block Chevy or a 348 or 409 Chevy "W Block" Engine (same as car 348 and

409 engines). These were replaced with the tall deck Big Block Chevy engines in the mid to late 60's.

The reasons they are Rare is a high parts failure rate, and common removal for re-power upgrades. I have seen a few in salvage yards that deal with medium duty trucks. These engines are not just HEAVY they are taller then a tall deck Big Block Chevy.

Tall Deck medium duty Big Block Chevy's come in 2 displacements. 366 &

427 C.I.D. Both will bolt in to a light duty (up to 1 ton) that has Big Block mounts. Charles

Well my current engine feels like it has no more torque than a worn-out Chevette engine. So yeah, a cam swap could be a good thing. But I'm not sure I want to do that, as it's something I've never done before, and it'll require tearing apart most of the front end to get it done. The cams are well under $200, yet I was quoted $800 labor for a shop to do it. I'm not spending another grand to make my 350 run like a 350.

I'm ready to sell the 350 as-is and cut my losses. I could put the money toward the 292 build-up. I have found them re-man'd with warranty for about a grand + shipping and core charge. That would basically be a drop-in. I could re-cam it later for even better torque, although I just emailed the seller about whether the engines are ready to ship. Maybe I could have a different cam installed by them before it ships.

I'm in the process of mapping out a timeline that I want to stick to in order to have the Blazer back on the road with the new motor and axles by the end of October. That's when I'm planning my cross-country vaction/roadtrip and I want to be driving the K5 when I do it. Some of the places I'll be going will require a 4x4 vehicle and the girlfriend's Tahoe isn't up to the task (not that she'd want it off-road even if it were!). I'll also be pulling a small pop-up camper more than likely, as we'll be camping along the way.

The list of items is extensive, but I think I can manage it:

292 motor rear axle (either rebuild or replace) regear front axle transfer case (apparently my 208 has metal shavings inside)

While I'm under there, I may pop in a few inches of lift and go up to a

33" or 35" tire. It all depends on how well things are going as I reach the end of the my schedule.

That makes sense, as most of the 292-equipped trucks I've seen or read about were work trucks intended for hauling heavy loads.

~jp

Actualy they came with a 5.14 (neighbor has one) and back in 60's 3/4 tons came with 4.57's (I had one once) The used a Eaton HO72 rear axle that came in a 4.57 or 5.14 hence the odd number instead of usual 4.56 or 5.13

----------------- TheSnoMan.com

Jon,

Just some ramblings here....but I'm trying to get some more grunt out of my 454 in my truck, not that it's a dog now... but what I've been pointed to over and over is the roller cam conversion kit from comp cams, specifically the 266HR. For my app it's like 900 bucks....but according to desktop dyno(and quite a few guys on 454ss.com) it will give me 550 ft/lbs at idle...from a current 300 and something(peak is

385 at 1600 rpm stock). Not sure if the same would apply to your truck...but hey as long as you're throwing around ideas, might want to at least take a peek for your 350.

BTW...this is a great thread I've learned a ton about engines I never knew existed.

Ed

Good suggestions are always appreciated! Well, like I said, I'm ready to dump the 350. Not because it's a bad motor, but I'll need to throw even more $$$ into it in order to get the performance I need, and since the Blazer is no longer a daily-driver, this gives me the opportunity to do something different, hence the decision to go to a straight-six.

I ran across a new product last night that looks very promising to add gobs of low-end torque. The inventor was taking a lot of heat from the "pros" in the beginning of a thread that he started on another forum, but they're starting to come around. I'm eager to see where it leads.

Check it out:

Hey, that's what it's all about. I still very much consider myself a novice. That's why I'm on here so much. I've learned a great deal in the last couple of years or so.

~jp

The smogged 454 suffers from a restrictive intake, heads and mild cam. A different intake and cam will wake it up a lot but no 550 ftlbs at a idle unless you supercharge it. Big Blo9ck respond a lot better to dual exhausts than SB's do too.

----------------- TheSnoMan.com

wow 550 ft-lbs at idle!

Were these calculations done at "wide open throttle" as ratings usually are? I can't envision that torque with idle fuel.

It is hard for me to imagine this thing running at a steady state condition such as 800 rpm and WOT. I guess if you pulled a Terex Titan down I-10, that's what it would take.