Jim G’s SLURP Project – Posting 11: 6 Cool motors that are not right for SLURP, & 2 that are!
This posting is one in a series. If you have not yet read the earlier postings in the series, you’ll need to, as this posting won’t make much sense without having done so! Just do a search using the word “SLURP”.
In my last posting, we explored the dyno charts of our forefathers. Our dyno results for AD trucks generally, and Red specifically, showed us that more power could be helpful in a modern highway environment (and is always nice), and I asked for suggestions on what cool engines could be candidates for a transplant.
In this posting, we’ll examine what I found on several engines that you guys suggested that I researched, and for each explain why my enthusiasm for them was less than great. Then, we’ll look at one engine that looks pretty good, and one other engine family that rang almost all the prize buzzers!
The first approach I considered was souping up the 261 I already have. That has some pluses, a big one being that I DO already own it, and it’s already engineered into the vehicle – no cutting or fitting required. But it also has some shortcomings. It would cost $3500, would barely hit 250 horsepower, and would be maxxed out at that point with no future upgrade path. So, no cigar. Besides, it being so newly completely rebuilt (completely rebuilt professionally less than 5000 miles ago), I can get decent money for it selling it to someone who wants a very faithful AD restoration but appreciates the fact that my 261 is far stronger than the stock 235.
I considered also using one of the later 292 inline sixes. That would be suitably retro, and these engines had stronger lower ends than the 261 (more bearings), but they too are limited in the same way as the 261 with that non-crossflow head, with the performance door slamming shut before we get even close to our minimum target of 300 crank horsepower. They are also very expensive to build even to that modest performance level, because of the proprietary tricks involved to get whatever power CAN be gleaned. Again, no cigar.
The Buick 215 aluminum V8 was an intriguing one to investigate. This was an engine, produced very briefly in the early 1960s, and then sold off to Rover in England when GM figured the “temporary” public pre-occupation with fuel mileage was over. It weighed only 320 pounds fully dressed! That’s about 255 pounds less than the 261! But, again, it would cost a lot (one quote was $7500) to get one built in the larger 4.8 displacement that Rover ultimately bored it to, and even with that displacement, 275 crank horsepower was the limit according to the specialty shop that builds them, and that is attainable only if you have room for headers without hitting the steering. There would be no upgrade path beyond that 275 crank hp. Sigh . . . no cigar.
The Pontiac 250 Overhead Cam inline six was next. This was a racy little 230 and later 250 cubic inch engine brainchilded by John Delorean while he was at GM, that was available for 3 or 4 years in Pontiac Tempests and Firebirds. It had a redline of 6500 rpm, and came in two versions, that were about 160 crank hp and 215 to 230 crank hp (saw both figures quoted). But, these are frightfully rare, corresponding costly, very fragile (significant camshaft bearing issues), and ultimately struggling to hit 300 crank horsepower after only truly heroic measures have been taken. And just TRY to get one fixed in Anytown USA if it hiccups. Again, it is hard to get excited about spending the money on one.
Then there is the nostalgic Chevy 348 “W” engine. This is incredibly heavy – heavier than the 261 even – and VERY wide, so there is no way to fit it into Red gracefully. Another casualty.
Then we have the relatively new GM Vortec 4.2 liter inline 6 used in a number of SUVs. This is a high tech engine with double overhead cams, 4 valves per cylinder, and variable cam timing, that delivers 270 crank horsepower in factory trim. It weighs about 435 pounds, which is good too. The big disqualifier is that it requires a computer, complex wiring harness, and an army of sensors in order to work. This violates the SLURP guidelines pretty significantly, so again, no.
That brings us to the Chevy smallblock – everyone’s answer to best bang for the buck. And for good reason. The engines are relatively inexpensive, lots of used ones available, tons of GM and aftermarket soup-up parts at very competitive prices, and you can get it serviced just about anywhere! Even pedestrian versions come close to 300 crank horsepower, and that is just the foundational number; it is relatively easy and also inexpensive to buy these, or get them souped up, well PAST the 300 to 400 crank horsepower level, into the 500s, without supercharging or nitrous. You can also get one repaired ANYWHERE. This WAS looking like the winner, since I had ruled out the LS engine series because I “don’t want no stinking computer” and all the sensors it requires to do anything useful!
But, then I read about the carbureted versions of the GM all aluminum LS engines that both GM and Edelbrock are now supporting. Wow. The LS engine series was designed for fuel injection and thus “dry” intake flow (the injectors that spray the fuel are literally just before the individual intake valves), but you’d never guess that when you look at how these engines perform when fed an air/fuel mixture via carburetor. The raw performance, across the entire rpm range, is virtually identical to the EFI version! Now, I’m sure that the fuel mileage will be lower with the carb versus injection setup, but if I can use an LS engine without the complexity and cost of the computer, the wiring harness, and the number of sensors needed to provide the raw data to the computer, I can live with some reduced fuel efficiency. I really like the weight reduction this LS series engine offers: an LS1 weighs about 430 pounds or less fully dressed (add 65 pounds if I go with a less costly “truck” version that has cast iron block versus aluminum block). That’s about 100 pounds less than a smallblock Chevy with aluminum heads, and about 150 pounds less than a smallblock Chevy with iron heads, or my existing 261!
Here’s what clinched it for me: I modeled a plain Jane crate version of the LS1 available from GM in my simulation software that simulates Red with different engines and transmissions and vehicle weights. Even withOUT any weight reductions beyond the reduction achieved by simply subbing the LS1 and a 700R4 tranny (saves almost 200 pounds), the graphic below shows you the performance outcomes:
http://i252.photobucket.com/albums/hh16/JimGnitecki/RedwithLS1crateengine-700R4andnooth.jpgNote that Red changes into something resembling a steet terror, because IF you can control the traction (we might not be able to), with half a tank of fuel and a 175 pound driver, he hits 60 mph in under 4 1/2 seconds, and runs the quarter in 13.10 seconds at 103 mph!
It gets better.
If you assume the additional weight savings, which I HAVE already verified as being achievable, that get Red to the magical 3000 lb. weight before fuel and driver, and then add the fuel and driver in, you get the graphic below.
http://i252.photobucket.com/albums/hh16/JimGnitecki/RedwithLS1-700R4-weightreductions.jpgHere, Red hits 60 mph in 4 seconds, and runs the quarter in 12.74 seconds at 106 mph, again assuming we can somehow manage the traction.
And remember, this is just your garden variety LS1 crate engine, or a used LS engine from a wrecked Corvette or Camaro.
If you install Edelbrock’s ENTIRE kit, which beyond the intake, carb, and ignition, adds a matched cam, the results get REALLY intense, as seen in the next graphic.
http://i252.photobucket.com/albums/hh16/JimGnitecki/RedwithEdelbrockLS1-700R4-weightred.jpgNow Red hits 60 mph in under 4 seconds, and runs the quarter in 12.27 seconds at 112 mph, again assuming we can somehow manage the traction. Remember, this is a pickup truck! I can live with that future upgrade path . . .
Finally, if you really want to get silly, you put on a Magnuson supercharger designed specifically for the LS series, and add 100 REAR WHEEL horsepower.
http://i252.photobucket.com/albums/hh16/JimGnitecki/RedwithsuperchargedEdelbrockLS1-700.jpgNow Red hits 60 mph in about 3 1/2 seconds, and runs the quarter in 11.5 seconds at 124 mph, again assuming we can somehow manage the traction, and at this point, I doubt we COULD manage the traction (you can’t get tires wide enough into the fenders), but highway acceleration would surely surprise a lot of modern performance car owners! Don’t even LOOK at the projected top speed in the graphic – you don’t want to be driving a leaf spring suspended refrigerator-tall 53 year old missile at anywhere NEAR that kind of speed.
So, as far as I am concerned, we have a winner: an LS series engine equipped with non-EFI intake, carburetor, MSD ignition box that PLUGS into the coil packs and reluctors (no mods required), and a control kit for the 700R4 ($30 more). It is just plain hard –no, probably impossible, to beat the combination of performance and value.
Second place is the Chevy smallblock, in case we find a much better deal on one of those versus an LS series. Yes, you can criticize this as “EVERYBODY does that”. But, sometimes there is a darn good reason that “everybody does that”, and in the case of the smallblock, it is simply a GREAT combination of cost, performance, simplicity, wide support, etc. You sort of have to be pretty contrary, and determined to be different, to say “no” to that. As for nostalgia, remember that the smallblock has been around since 1955, and available in Chevy pickups almost that long, so it’s definitely respectful of history. In fact, the smallblock is perhaps the longest running engine series ever.
The LS engine of course is “modern”, but it’s the son of Smallblock, so has good genes, and we can use either one or TWO 4-barrel carbs to help give it that “oldtime” look. Then we can revel in its power, its future expandability, and the immediate improvement it makes in weight distribution on Red, since both it and the 700R4 are forward positioned in the chassis, and will very favorably change the weight distribution over the 261 plus cast iron Hydra-Matic.
This is kind of the way I am thinking right now.
What do YOU guys think?Jim G
