The Stovebolt Site Forums The Shop Area The HiPo Shop Did you guys see Hot Rod this month???

I thought this was pretty interesting. Hot Rod (not Car Craft...) magazine did an article this month on hotrodding the straight six Chevy. The rods and pistons are quite a bit different, I think I read they use certain V8 rods and pistons, and then bore the cylinders to match. The heads are ported pretty heavily, or you can get the modernized aluminum head.

These guys were pulling 1 hp/ci or more. With the available Clifford intake and a Holley carb, these motors made big power to about 4800 and then fell on their face. However, either fuel injection, or a custom manifold boosted the rpm ceiling to almost 6000 rpm and boosted power on these motors to about 1.24 hp/ci. These things were making over 300 hp!

Although a V8 still has more potential than that, these guys aren't done yet. There is a turbocharged I6 in the works next.

Are we gonna see 400+ horse Inline sixes in these trucks now? Wow.
Check out the article, it's really interesting.

I didn't see the article;what size sixers were they building? I have a 292 in a C-60 that could sure use a little more power...

what i would like to see is someone to put the new 275 hp straight six in a AD truck. also i think it should have gone into the SSR. RON

I did not see the article either. Where is it?

It's in the June 2005 issue of Hot Rod magazine, on page 108. It's on the Chevy I-6's, not the GMC's. But I wonder if they might carry stuff to hop up GMC's too.

The biggest thing is, they used Chevy big block V8 long rods, for a tall deck. Then they used some kind of a Chevy aluminum piston and overbored the I-6 to that size. This significantly strengthened the rotating assembly to allow for higher rpms safely.

The next big thing they did was to either port the lump port stock heads, or replace the head with a modern redesign in aluminum, with beautiful direct port paths and heart shaped combustion chambers for high swirl and improved compression ratio.

The most powerful I-6's were either the port fuel injection engines or the one carbureted engine that had a custom intake fabricated. The Clifford 4bbl intakes were only good to 4800 rpm before they fall on their face.
With EFI or the custom intake, these things were pulling hard to almost 6000 rpm before they were done!!!

There was a 292 that snagged around 300 hp, and then a 250 that had just a little over 300 hp, but a little less torque than the 292.
And then at the end of the article they talk about having a turbocharged fuel injected I-6 being developed.

Wow, can you imagine a 400+ horsepower I-6? How cool is that?

I've gotta tell ya, I like the V8 converted Stovebolt trucks a lot, but with these kind of power options, it would make me think twice. If I could spin the motor to 6000 rpm and have a big turbocharger shove me hard into my seat with an inline 6, I'd consider it seriously over the hassles of a V8 conversion.

They didn't talk price. I'll look into that and post back here. That's the other thing. How comparable is it to building and converting to a V8?

Then again, with all these improved numbers more than tripling the amount of torque into the drivetrain, another important question comes up...How much torque can the SM420 or SM465 transmissions handle, and how about the stock rear end? Are they up to the task of 300+ hp?

There's a cool article in the July '05 Mopar Muscle about a remote mount turbo system from a company called Squires Turbo Systems(www.ststurbo.com)It's shown in new hemi truck. Be really cool to see what it would do for a hopped up 292.

the rock crawler (6+:1 low ??) SM 465 or 420 should be able to handle it but don't speed shift. they are pretty bullit proof. 420 is hard to find parts for. How much can the T5 handle??

I'm not sure why ya'll think an SM420 or SM465 can't handle a measely 300 ft-lbs of torque from a built I6, they come behind big blocks, Jimmy V6s and and detroit diesels. You ain't goin' nowhere quickly with one, but you can tow a house around.

I think you'll be munching second gear synchros and overdrive on the T5 weekly unless you are careful. You could improve the longevity with some mustang or merkur gears.

As for I6s producing good power, look at the jeep 4.0 with port injection, easy 200 hp with an almost 20 year old design.

If you go to the clifford website, you can download their R&D build sheets in pdf format. They will do the head for you to their "secret" specs (big bucks), but I think it is probably just a good porting. They have specs to turn an OHC pontiac 250 sprint motor into a 302 that will bolt in where your chevy 250 went.

go to the web site in Hot Rod's article - BIG BUCKS to do what they are doing!! more than i can spend anyway. i am trying to figure out the 4.2 canyon/colorado swap but wiring/software is the big problem i am having trouble getting answered!

Hope you find out about the wiring/software. Wish that was more simple to cure.

Yeah, the big bucks issue is probably why it would still be more viable to drop a V8 in the truck rather than to soup up an inline six.
And even a mild V8 could potentially make more power than a built I-6 anyway. Still, if someone wants to keep a stovebolt and have his power too, 300+ hp out of an I-6 is not bad. And you can keep it mostly hidden from view.

Ray
PM me if you need to, I have not done this swap, but am very comfortable with the wiring it takes to do these swaps and will help you through it as I, too would like to find a 4.2.

Yup, that's for sure. In fact, I think Mr. Clifford, from Clifford Performance, used to race stovebolts against the early V8's with good success.

No doubt you can make a Stovebolt perform, but the Hot Rod article seemed to indicate that the horsepower was still limited to the 300 horse range. It's the super flat, strong torque curve that makes these engines great. So I have no doubt that they'd pull the wheels up, built right.
But the cost might be pretty high, to build one of these I-6's, especially if you get the EFI set up and the modern aluminum head.

If I had two of these trucks, I'd definitely build one of them with an inline 6 built up, and the other one with a V8. There are times when I'd like both set ups for their own merits.

The upper H.P. limit on the built I6 engines is far from 300 H.P. Leo Santucci has a 292 cu. in I6 that makes in excess of 700 H.P. That's turbocharged, runs the 1/4 mile in less than 10 seconds. My basically stock 292 with 3 Webers and a cam is over 300 H.P. and very streetable. Main problem about the I6 is cost, you can build a V-thing for less money and makes more H.P., but everyone is impressed with a strong running I6, and the sound of a good hot I6 is fantastic.

Have you got a sound file you can e-mail me by any chance...of your engine? I'd be interested in hearing it. I've never heard a hopped up I6.

Does Leo Santucci have a website?

The reason it costs more is almost everybody has eights, Heck you can buy billet 8 junk at 2a.m. by phone.
BUT
Inliners are WAY cool. If you're interested in hopping up a sixer and want info on head work, intake and carburation ideas, split exhaust, rockers, HEI, and more ...
The point here is what I remember from my old high school days, when you change one thing that starts the dominos falling and pretty soon that small project got bigger.

check out:
http://www.customdesignperformance.com/
they advertise in 'inliners' also
http://www.customdesignperformance.com/leo/leo.html
and cliffords (as mentioned above) as well as this site:
http://www.truckworld.com/How-To-Tech/Chevrolet-Engine/Chevy-engine.html
Buffalo Enterprises Contact Steve @ (360)652-7684. an old knowledgable sixer and great guy.
join: http://inliners.org/ ,
http://www.stoveboltengineco.com/ talk to Tom.

As far as putting an L~6 into stovers, the motor mounts need changing, 700R4 or a T-5 w/ all camaro guts are wonderful backers to it, what ever pleases you. 420's and 465's are very strong but not what you want here if this is your goal. You can pump out tons of HP out of an L~6 but then the other factors come into play. Change out the straight front axle, or at least change kingpins, install disc brakes and a dual master. An IFS??. You have already changed out the rear end and probably have good brakes back there. But I have to say I'm looking forward to my sleeper 51 bolt. Buy Leo's book, it's a good start and may save you some headaches, but many of us wish he had put more in about streetable 6er's. Read as much as you can about your new project. Good luck having fun w/ her.

The Hot Rod article also mentioned that they were building one of the modern chevy I-6 engines and dropping the EFI for a multi carb setup. They bragged it would be pretty hot stuff. Might be a cool way to get that engine swapped in without the wiring hassles?

Hot Rod Dad, Go to Inliners.org there is information regarding Leo Santucci's book on hopping up the late 6 cyl. engines. It is mostly oriented towards racing applications, but milder versions for the street are similar. Sorry no sound recordings of the hot 6, but remember the old 235's with split manifold and twin Smitties? Sounds like that. If you are at Bonneville the GMC or Chev 6 make a sound you'll always remember. I used to race in the early 50's and a guy ran a 1934 F**d coupe with a 12 port GMC and it was FAST and VERY LOUD! Later he put the 12 port in a dragster and nothing could touch him. His name was Frank Iacono and I think he was from the San Pedro area of Los Angeles.

ok, just finished reading Hot Rod - great article - made me drool all over myself. Now check out JP magazine Aug '05 for another way to go. It's about a turbo kit for the Jeep 4.0 I6 that looks like it would work on a Stovvebolt with out all the excessive cost.

How about 500+ HP on a natuarally aspirated 301 GMC with a 12 port head? It's been done and in a dragster ran an 7.97 @168.

Veeerrrry cool.

As stated in the article, 'nothing beats cubic inches except cubic money'.
I am building a 292 now, according to the specs in Leo Santucci's book.
I want my 292 to be unique, (lots of torque to beat the 350 crowd) at least from stop light to stop light.
NOW: Depending on exactly 'what end result' you desire, the price ranges from approx, $3000 for basic to over $7000 to get up in the 350 HP range.
I want a thumpin' six that sounds great, smokes the competition short distance, but also one that will 'cruise' on the highway at 70 mph AND most important of all, that does not have to be rebuilt every 2 - 3,000 miles.
According to my specs to acheive that, and phone calls to Cliffords and other's, that's about a $4000 - $5000 motor.
Different strokes for different folks.

hey guys,i have an 82 k10 250 i6,465,np205 and soon to be 1ton turning 35" tires.
i need more power!please dont let this post die.
George

There's an NHRA guy that runs a 400 horse turbo-charged 230 in a ford Anglica; I thinks it's a 1937 model car, not sure what year the engine is. He says he prefers the 230 because of the shorter stroke; ya get more rpm quicker. Big HP out of inline engines is nothing new. BUT it's always cool.

Boo

you want a powerful I6 motor, go with a late model supra, those motors and drivetrain can take upwards of 6-700 HP on a stock motor with jus simple turbo upgrades. Its also a good looking motor. Just food for thought, im sure most you would barf at the idea of a Toyota motor in there Chevys, but if I ever find one for a good deal, no question it would go in my 56. With the right custom valve cover it would look pretty good in there.