Keeping my I6 250...what to do?
 

I am keeping my I6 250 and want to know what to do to it. I have changed plugs and wires and replaced the valve cover gasket. Replaced the fuel filter and did an oil change.


What's next?

Re: Keeping my I6 250...what to do?
 

Here are some pictures of it now.

Re: Keeping my I6 250...what to do?
 

Are you looking to do some modifications? You could look at buying some headers to do dual exhuast and let her breathe a bit better, change from your points setup to an HEI unit. That's all I've done to my 230 yet.

Re: Keeping my I6 250...what to do?
 

Explain the Points to HEI and why one would change.

Re: Keeping my I6 250...what to do?
 

Definitely get an HEI look for late 70s straight sixes in the junk yard (Novas, Camaros, Malibus, & pickups) or get a new one (Ebay $60-$120). They are 100% more reliable. Dual exhausts sounds great on these motors, and an intake, carb, and cam swap will wake that little guy up too. Check out Clifford Performance if you wanna get hooked and spend all your Christmas money!
http://www.cliffordperformance.net/M...gory_Code=C250

Re: Keeping my I6 250...what to do?
 

1. HEI unit. ignition coil into the distributor cap, eliminating the need for a coil wire and adjusting them. HEI's produces both a hotter and fatter spark', huge HP gains.

2.2 barrel carb intake "more fuel flow"

3. go to pick and pull and get a new model exhaust manafold from a inline 6...maybe out of a truck of the 1980-85. they are 1/2" bigger....its like running a header..and run 2 1/2" mufflerand pipe.

Re: Keeping my I6 250...what to do?
 

HEI is way more reliable and produce a hotter spark. You'll have to probably run an ignition hot 12V to power it up because I think the points coil is low voltage. They are 1 wire hook up and easy tach hook up too. Plus they are a cleaner look than the points set-up.

Re: Keeping my I6 250...what to do?
 

This all sounds great.

Re: Keeping my I6 250...what to do?
 

Keep us updated on what you get done. We all have to stick together cause Inliners are like Mopar Guys ........ Crazy and Outnumbered!

Re: Keeping my I6 250...what to do?
 

I can do that. And I certainly notice that:)

What kind of gas mileage should I expect once I'm driving my truck?

Re: Keeping my I6 250...what to do?
 

Depends on gearing and trans but don't expect over 16

Re: Keeping my I6 250...what to do?
 

As everyone else said - you have to go electronic. Better starting, more power, easier maintenance, better mileage.

I've pulled off 20 mpg with a 250 before on a steady cruise, but 16-18 is the norm for me.

If it's a '67 250 I usually update to the '68-'72 monojet.

You might want to pop a side cover, pull a lifter and look at the cam lobe. If it looks worn it's not too hard to put a new cam in and it will really wake it back up...

Re: Keeping my I6 250...what to do?
 

Will the 80-85 manifold fit on a mid-sixties 230 L6?

I think GM stopped making the 230s around 1970 or so, and mine needs a new manifold. If a newer and better model out of a bigger L6 would work I'd love to make this change.

Thanks!

Re: Keeping my I6 250...what to do?
 

If it's a '67 250 I usually update to the '68-'72 monojet.

You might want to pop a side cover, pull a lifter and look at the cam lobe. If it looks worn it's not too hard to put a new cam in and it will really wake it back up...[/QUOTE]

Tell me more...... :)

Re: Keeping my I6 250...what to do?
 

The exhaust manafold will fit....I have one

Re: Keeping my I6 250...what to do?
 

For future mods (not just the engine) you can go to power steering (pump mounts are harder to find) and brake booster (you'll need the also harder to find offset air filter set up). Both of these are just things to tinker with but keep you looking for I6 parts. Hoses and wiring are things to go through as well. Everything thats black in the pic is new stuff on mine.

Re: Keeping my I6 250...what to do?
 

Tell me more...... :)[/QUOTE]

Well, '68 was when the redesigned monojet was introduced. I've found it easier to work on and it performs well. It's a direct bolt-on so I did that to my '67.

I had a '70 Bel Air with a 250 that was not well maintained. It ran, but didn't have a lot of power. I popped a lifter out and looked at the cam lobe. It was worn way down.

For not much money I got a stock replacement cam from JC Whitney and popped it in. Now the valves opened all the way :metal:. Made a noticeable difference in power.

Re: Keeping my I6 250...what to do?
 

i got excited when i saw this picture!! i thought mine was actually road worthy hahaha

i did the petronix system in my distributor. i wanted to keep the look of the coil (the original look)

Re: Keeping my I6 250...what to do?
 

sorry if this is sideways too

Re: Keeping my I6 250...what to do?
 

Just an FYI, if you want your photos to upload with the proper orientation, when taking a picture...

Re: Keeping my I6 250...what to do?
 

If you have photos that you have already taken with the home button on the left, top or bottom, they will have to be rotated in a piece of software to correct the issue. Even though the appear to be right-side-up on your phone or computer any vBulletin forum (like this one) will not display them properly.

If you would like to know more about how to correct the orientation of images you've already taken please see this post http://67-72chevytrucks.com/vboard/s...d.php?t=743225

Re: Keeping my I6 250...what to do?
 

In '79 the 250 became known as the 4.1 liter Pulsair with integral intake and totally different exhaust manifold. The manifold (80-85 ?) mentioned would have to be from a 292 and not all 292's. It is larger with 3-bolt outlet, but very hard to find and not worth the effort to change the exhaust system for marginal if any improvement.
If you want to change the exhaust, get tube headers and run dual exhaust all the way back.
That change alone to the engine will still give only marginal improvement. You still have a 8:1 cr and not exactly a performance head.

If you are able to adjust points properly and have a dwell meter, keep the stock distributor. The HEI has two advantages. You don't have to adjust or replace the points every 10,000 miles and it will provide a better spark over 6,000 rpm. OK, three, it will fire old, dirty, misadjusted spark plugs, long after their usable life with a points ignition. A remedy is to check and clean every 10,000 along with the points.

It won't give more power or fuel mileage than a well maintained point ignition.

25 years ago I installed an HEI, because my truck was my daily and only driver. I was driving 60 miles a day for work only and the interval for the points needing attention was more frequent than I had time for.

If you want to make changes that will put a smile on your face and make you want to get behind the wheel, add power steering and AC.
These are notable, worthwhile improvements that give the biggest bang for time and effort.

The next thing is gearing. That can be corrected with new rear gears or depending on the current gears, possibly with an over-drive trans.
Unless that has already been addressed, you're probably driving the slow lanes or side streets. Get the right gears /trans and get out on the highway and enjoy.

The one thing that you haven't been told is that the sky will fall if you don't change the Alt to a Internally regulated Alternator. B.S.

I have AC, HEI, electric fan, elec brake controller, Bluetooth stereo and stock alternator.

Re: Keeping my I6 250...what to do?
 

Has your motor been rebuilt? Sure is clean.

Re: Keeping my I6 250...what to do?
 

thank you very much for the picture advise....several of the pictures were taken before the tips..

thank you again

Re: Keeping my I6 250...what to do?
 

I agree with many posters above. HEI (Pertronix OK, but if a failure, HEI parts available inexpensively anywhere around town same day.) Power Steering. I'm OK with manual brakes, even discs but YMMV.

But the best thing you can do for your 6 cylinder is a T5 transmission from an S10 with a 4.3.

I really like the way a lowered truck rides as well. Drop kit, swaybars and gas shocks and my '69 is a pseudo-sports car.

Re: Keeping my I6 250...what to do?
 

Here's a few things that I'm surprised no one has mentioned yet:

Look at installing a lump port kit in your head, those inline six heads were not designed well, and lump porting will vastly improve flow. Heck, even if you cut out the bolt bosses on the intake runners your flow numbers will increase substantially.
This will also allow you to more properly utilize a 4-barrel intake & carb and headers.

Another inexpensive upgrade that a lot of guys do is swap out your stock slugs with a set of aftermarket 307 flat top Pistons. They'll fit your block perfectly, and greatly decrease your rotating mass.

Now you can choose a cam, something in the 260-280 range would work well with the other upgrades. Always install new lifters with a new cam, and a set of roller-tipped rockers would be perfect.

This is about all you would want to do to a little 6 banger aside from adding a turbo or supercharger which I'm not really a fan of.

I'm actually in the process of building up a 292 for one of my projects ('50 Chevy Deluxe).

I've got some +.040 Silv-o-lite flat tops
And a comp 280h cam
Plan is to acquire a lump ported head and go from there.

Good luck with your 6. It's always nice to see one that's been beefed up, and they have a great sound.

Re: Keeping my I6 250...what to do?
 

I have a different opinion. I have run the base model Pertonics units for decades now and not had a failure. But if I ever did, the points and the rest of the pieces are bagged up in the glove box ready to get me on the road again. That isn't an option for an HEI, unless your willing to carry a spare distributor. Tomatoe or Tomato.
And as far as what else to do with your 250. Drive the wheels off it man! :metal:


P.S. (Pertronics got bought out and the company's new products are not up the the engineering standards of the old owners. The old line of products are still as good as they used to be. We wont install any units but the basic ones. Lesson learned the usual way.)

Re: Keeping my I6 250...what to do?
 

I run Petronics ignition, never changing points again (Or filing them on the side of the road to get home) is nice!

Re: Keeping my I6 250...what to do?
 

I had a Pertronix Ignitor II on my 292. Worked good for about 7 years, then it would mysteriously cut out at 65 MPH, 3000 RPM. Engine would ''black-out'' deadrolling at freeway speeds until I could kick in the clutch, turn ignition Off then On, and pop the clutch at 55. I went back to points for a year. One theory was Desert Heat, another theory was it was getting spiked by high voltages from the EVR.
I emailed Pertronix customer service about it. They said send in the Ignitor II and they'd check it out. So I sent it in and never heard from them again.
Now I have a remote coil HEI and I'm happy with it.

Re: Keeping my I6 250...what to do?
 

"remote coil"??

HEI that has the coil still mounted to the block and not inside the cap?

i'm interested...

Re: Keeping my I6 250...what to do?
 

Yeah, on the '75-'77 4.8 L6s [292s] there was cap interference with the big cap hitting the passenger side of the engine. Some fancy finned-aluminum custom side lifter covers had a dish milled where this occured, but I had clearance issues with stock covers.
Mounting the coil on the head [basically where the points coil went] lowers the action. It's a different cap too.
I can't find the pic. It's still on the SD card and not in Pictures. Working on it.
Got 'em.
Low Boy cap and custom coil bracket.

Re: Keeping my I6 250...what to do?
 

I got a couple of caps from ebay, They were $5 each. The pigtail I got from RockAuto. Coil from Merle's Auto Parts in Tucson. Order parts for a 1976 Chevy C/10 w/4.8 Liter L6 [292].
Had to fab my own bracket to hold the coil.
The OEM bracket straddled between the front bolt of the rear lifter side cover and the rear bolt of the front cover. There was a 1/4''-20 stud on top of these bolts. Coil mounted on a U-shaped bracket between the lifter covers. Hard to find now.
I mounted my coil upside down for better reach to the distributor pigtail. Looks cleaner, and plugwire terminal doesn't stick up.
Coil is attached by 2 bolts on ''front'' of coil. Adequately secure and allows reach behind to #3 sparkplug.

Re: Keeping my I6 250...what to do?
 

WOW!! thank you very much!!! i will for sure keep this in mind. i want to ride this little guy for a while then revisit this thread for the info about the cam upgrade and deffinatly the HEI

thank you again for the pictures and info!!!

Re: Keeping my I6 250...what to do?
 

This is how the factory mounted the coil. The two center most bolts on the side covers have threaded studs above the hex.

Re: Keeping my I6 250...what to do?
 

thank you!!

Re: Keeping my I6 250...what to do?
 

Found a better picture of the coil on my computer.

Crazyjeenyus, is giving you good info about the engine, but in my opinion, without the other changes to the truck, more power won't make it a more enjoyable truck.
My 292 has the LPG 9:1 pistons, 1.94 In valves, roller rockers, cam, Carter AVS, Clifford, Hedman, but I was still in the slow lane with the engine screaming its heart out. It wasn't until I changed the rear gears was any of that worth while and it could run in the fast lane with anyone. I know the stock engine configuration would have been equally happy with better gearing.

Before the power steering, I always felt like I was wrestling a grizzly in the cab when I was trying to park it. Power steering allows you to get rid of the giant steering wheel they put in there to give you leverage to wrestle the grizzly.

AC speaks for itself. There's nothing fun abut sweating in a truck cab no matter how much power it has.

Re: Keeping my I6 250...what to do?
 

hahaha wrestling the grizzly....i agree
A/C as well. i told the wife how much fun it will be to meet and hang out with "old car guys" and cruise. she said, "will there be A/C"? hahaha
pretty sure that will be the first "upgrade"

what rear end gear ratio would be the best? highway gears was in the plans down the road

i haven't checked mine. its all stock '67 swb with 250 engine

Re: Keeping my I6 250...what to do?
 

Added this to "Truck Work" favorites folder! I have the 250 also and it could use some upgrades later on.

Re: Keeping my I6 250...what to do?
 

Richard: What are the two vertical 3/8-18 bolt holes between Cyls 3 and 2 used for? Hangover aircleaner support? I've always used them for coil mounting. When I had points, I hung a big square Mallory Voltmaster coils on those 2 holes. They were vacant on my engine.

Re: Keeping my I6 250...what to do?
 

>> two vertical 3/8-18 bolt holes between Cyls 3 and 2 used for? Hangover aircleaner support?<<

Yes, but also for the AC compressor bracket. That last coil picture looks like it was taken before the AC installation. I use the bottom hole there and the two holes at the front next to the #1 plug.