What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Inline or V6 Vs 350 comparison?

chevyfumes

chevyfumes

Court jester
- In Memoriam -
Joined
Feb 24, 2000
Posts
38,699
Reaction score
465
Location
Watch for the muzzleflash!
What kinda power/torque could you achieve from an inline or V6 Vs a 350.

Interested in how well one could be built without it costing thousands in comparison to a standard 350, especially in terms of fuel efficiency/ MPG.

Would it even be something to consider? I know a lot of you probably just think go 350, but it makes me wonder with the eventual prices of fuel becoming something so ridiculous that I can't afford to drive to the corner store.

This would be in a 67-72 SWB pickup. On a serious weight reduction diet if necessary. Very mild wheeling, mostly for hunting/ camping.

I'd at least save $20 or so a year on two less spark plugs..:haha:

Thoughts????

I know some of you making millions of dollars a year, still run BB and while a 502 would be pretty damn cool.....:haha: doesn't take long to scan through CL and see a nice rig for less money simply because it has a BB under the hood.:popcorn:
 
I'm sure everyone's gonna start beating the LS drum, but a strong 292 would be pretty badass, and make acceptable torque. Not sure about the mileage though.
 
I had this exact truck but 2wd and 3 on the tree. It also had 4.10 gears.

I very rarely took it over 55mph (like it could go any faster:rolleyes:). I got upper teens and lower 20's on mileage. The motor was more than powerful enough to get out of its own way.
 
That's another thing, I'm not big into standing on the tall skinny pedal. I've been known to go the speed limit about 98% of the time but these days you do very often need to be able to get outta the way.:haha:
 
GWeakland620 said:
I very rarely took it over 55mph (like it could go any faster:rolleyes:). I got upper teens and lower 20's on mileage.
Click to expand...
If you don't go over 55 you'll get that kind of gas mileage out of a lot of motors. :)
 
The straight six has a lot of torque and will run forever, but I'm betting you won't save much in gas, they weren't known for ultimate efficiency.

There really isn't a practical reason for putting in a V6 unless you happen to have one around. You give up hp and torque, and if you want to build it up it will cost you more than to build a 350. The V6 is going to have to work harder to move that heavy truck, so mileage gains may not be substantial.

LS motors get slightly better mileage, however the cost of acquiring the motor and doing the swap may not pay off for a while.


The only significant mileage gain will come from switching to diesel, which again is going to cost money and time, and won't pay for itself unless you do a bit of driving.
 
power block tv engine power just did a 4.0 6 cyl jeep build with basic reman and aluminum head swap and it made great power .
 
I had a truck with a 250 and a 4 speed. I can't say anything for mileage but the engine was 0ver 40 years old and had plenty of power. I like the Inline engines but the shared intake and exhaust mounting setup seems stupid to me
 
My experience with inline 6's is in completely different vehicles.

I have a straight 6 200 CI in a 66 mustang and love that thing. I put a mild cam and a header in it and it'll scoot. I then put in a T-5 transmission and that combo works even better. With the inline 6, T-5 transmission, and 3.20 gears I get 26 MPG and cruise the interstate at 70-75 with no problem. One of the best things I've done to this car is to not put a V8 into it.

I also had a 300 CI inline 6 in a 91 F150 2wd. That engine had loads of torque, but only got 16 MPG.

FrontAngle.jpg
 
If you look at the comparison figures year to year, I don't think you'll find a 6 that ever put out more torque or HP than a V8 in the trucks. I poked around looking at numbers because the I6's seem to have this mythological stump pulling ability. The TQ (and HP) numbers from the factory say otherwise.

The majority of accounts from 6 cylinder truck owners I've seen is that their mileage is as bad, or worse, than a 350 or 305. Obviously the 400+ CID motors start to take a noticeable decline in MPG.

Per cubic inch displacement (or liters, your choice lol), I'm betting a straight six costs more than a 350 to rebuild, if you spec similar parts.

Smaller, efficient diesels are where MPG is at in a truck.
 
dyeager535 said:
If you look at the comparison figures year to year, I don't think you'll find a 6 that ever put out more torque or HP than a V8 in the trucks. I poked around looking at numbers because the I6's seem to have this mythological stump pulling ability. The TQ (and HP) numbers from the factory say otherwise.

The majority of accounts from 6 cylinder truck owners I've seen is that their mileage is as bad, or worse, than a 350 or 305. Obviously the 400+ CID motors start to take a noticeable decline in MPG.

Per cubic inch displacement (or liters, your choice lol), I'm betting a straight six costs more than a 350 to rebuild, if you spec similar parts.

Smaller, efficient diesels are where MPG is at in a truck.
Click to expand...

Some Dorian clockwork. Thanks man that's what I was looking for.

Guess the best idea is to try and get the best efficiency out of a standard 350,I figured even if I could with any 6 I'd be killing the deal in price for parts. That was my guess anyway.

Pipe dream. I'll at the very least need to start with a vehicle other than my modded vacuum cleaner to get me off...:haha:
 
79bonanza said:
The I6 prolly just had a lower rpm torque curve than a V8. Making them feel like they could pull harder
Click to expand...

The HP/TQ figures given are peak, so no, that's not quite it. They might have been flatter curves, I really don't know, I've never seen an I6 dyno run, and even then, the story under 2000RPM might be different.

Looking at the LS-series "curve" though, you see why they are such a popular motor.

I went through the same dilemma with the current rig, and a potential 6.2L swap. 25MPG is very inviting, but the work to get there after what I have invested in EFI, and how little I drive the rig, not worth the tradeoff.

If you look at the motor I'm running now, and the cost to "upgrade" to it from a quadrajet, when the ONLY difference was drivability (mileage is the same), that equates to a ton of money and technology to put in it and see no gains in economy. It's disheartening to learn the fact at your own expense, that full size trucks don't get good mileage. Unless you consider 25-30MPG good, and that's still going with a smaller diesel.

Now, do the math on a $1000 econobox that gets 40MPG (they are out there) and see how long that MPG difference will pay off for you. With the average annual mileage and average fuel economy for a truck, I figured the econobox would easily pay for itself within the year. That does not factor in additional insurance, maintenance, etc., but the fuel economy vs. cost difference there is enough to make it worth considering. A 25% increase in efficiency from a multi-thousand dollar engine swap is not quite so easy to recoup the cost of.
 
I cant see any square bodied 4x4 getting very good MPG with a gas engine large enough to pull it along. Between reciprocating parts, tire contact and aerodynamics it will be an uphill climb to maintain even double digit economy. Best bet might be a small displacement V-8 like a 267, 283, 307, 305 with swirl port heads, small runner intake, small tube headers, stock TBI style cam, HEI, small lean jetted square bore or like modded spread bore. With conservative gearing and tire sizes I would think that low teens to mid teens MPG could be achieved with todays fuel blends in average driving. The cost to put something like this together would be minimal as these engines are considered scrap to most people and can be had for a song.
 
So then if that's the case, is there even an argument between those and a 350? Taking into Consideration that it's been tapped for efficiency to maximum capacity?
Or does it just become a wash/ give and take scenario, price per part, MPG,availability?

Is there any beating the tried and true? That I guess is my bare bones question....
 
You must log in or register to reply here.

Latest Posts

Top Bottom