I built a 4.15 stroke .030 over hemi in a 66 block. Crank, rods, and piston set was available to me with CD of piston that supported 10 to 1 based on block decking and gasket choice. Even with the 4.15 stroke with mopar journals you have clearance issues to resolve. If your going to stroke bigger than it is a crank with chevy journals, with a stock block, otherwise you have block work to do in my opinion. A blue printed stock hemi motor will make plenty of torque and power. So to me, if it is not for racing, cost and penis size is what determines how big a motor you build if using original stock block. The more you over bore a 57 year old block the more risk to a crack/leak in my opinion.

Didnt think / know about these issues . So its Food for thought. Its the correct dated motor ( no vins on them in 66 ) And I really would rather not risk these kind of problems down the road.


Its 20 over now. And best I remember previous owner told me it has one maybe 2 sleeves in it already.

So odds are if there is this kind of risk . then stroke it is out of the question. The car is more than fast enough as it is for this old fart

for me my biggest concern would be $$$.
if you have a good stock crank then stay with the stock displacement.
if you need a crank then you might find a mild stroker rotating assembly the same or extremely close priced to stock parts. these parts might even be better quality than 50+ year old stock parts.
if you add displacement the chevy rod journal sized stuff is bolt in also.

yes.

It uses a little oil and if I set timing where it really wants to be to run the best. Race gas /. premium mix then becomes mandatory or it rattles like crazy , diesels on shut down something fierce. Ive got timing set at about 15 base right now and can get away with straight 91octane. And it will still ping slightly if I get stuck in traffic on a really hot day.



Dieseling on shut down usually means it lean. Which can also cause pinging. I have my timing locked out at 34 and no problems. Mine stared to do that and the intake gasket was blown. It was hard to figure out what was going wrong but my wideband alerted me. As bad as it was you'd think it'll be obvious but with a big cam and headers it wasn't. Get a can of brake clean start the car, rev it up a little and spray the heck out of it where the manifold meets the head. The brake clean will tell you if it's leaking and excess will evaporate quick and not hurt anything. Don't use carb cleaner it will melt paint and discolor everything. Solution I got rid of the Fel pro and installed Superformance gaskets and it cured every thing including the small amount of oil I was using.

Good luck, Mike

A friend passed along a tip to me that i'll pass out here. Setting dimples around the port with a drift helps prevent that. I would be checking for out of square also.

This hobby is about modifications and tinkering. The fact you are asking about a stroker means your lickin your lips and rubbing your hands together considering it. I say- if you have the means to do a stroker Elephant go for it! More cubes to tame those huge port heads and make for improved low end.

I've never really had a desire to build it as a stroker. Like I said. I don't race it or hardly beat on it. Outside of the occasional romp every once in a while. But is it really worth the upgrade if the lower end in mine is good and just needs refreshening and new pistons when that time comes? Hopefully that makes sense.


The original post was meant to ask. Why would you build one...unless it was a race car, street brawler or just for bragging rights?

I can see if if one is building one from scratch...then and only then. Maybe it's a no Brainer !!


In regards to better / more low end. I can up the gear to a 4.10 or maybe a 4.56 for more grunt off the line. But then,,, That takes away for my original intention and thats drive it . And drive it I do


A lot of people don't believe me when I say this. But I bought the car because of the color combination and the fact I helped build the car back in the early 2000s time frame so I know the car inside and out.
The Hemi just made that choice a little more expensive.

As a stroker there will be more ring friction at a given RPM and the engine will be less thermally efficient.

This is way down the list of desires of many owners, and that’s OK, but if you really strive to understand machines it can “bug ya” that it is not “better” in a deep sense especially if you realize how challenging each tiny advance is.

Same applies to making each part lighter AND stronger AND durable AND cheaper.

The old joke:
How’s your car project going?
- Way too much horsepower and too little traction!

Comes to mind.

The counter argument is:
Should my 1960’s model year automobile project be to retrofit in a “Flux Capacitor.”

Another joke:
Each year experienced lawyers grow more evil
and experienced engineers grow more picky.

In regards to the original question.
"Why build a stroker if not racing..."

There isn't a practical explanation. It's because we 'like' it. It's that simple.

If our only goal was to go fast in the most practical way possible, we'd all be driving used LS Corvettes. But we don't, because we like Mopars. We build Hemi strokers for the street because we like them, not because they make sense.

I built a 528 Hemi with iron heads for the street. It has somewhere between 10 and 15 thousand miles on it and uses oil the same way other have described, about quart low and then it's fine. It has a tiny stock style cam and 10:1 compression. If you're fine with how your car drives already, I wouldn't stroke it unless you just plain want to.

73DAD wrote: "There isn't a practical explanation. It's because we 'like' it. It's that simple."
Exactly - spot on! At our age if you have the $ why the heck not? Stroker kit will have more cubes and light weight components- Im sure a HYD roller cam will be the standard. Have an ultra powerful responsive street engine that is superior to the stock offering from Mopar 50 plus years ago. Big displacement big power all while utilizing a mild cam, compression and driver friendly ring and pinion ratio.

JMHO,

A 4.25" stroke is perfect for a Hemi, besides the displacement of adding more than an extra cylinder's worth of cubes you are also taking a whole lot of bobweight out of the bottom end. keep the cam mild and that way you work the big ports earlier in the powerband but still utilize them up high (at least as high as a factory 426)

Where you get carried away is when you add big stroke AND a big cam, then in order to really pay off you need to rev it as high or higher than the stock stroke.

Build the best of both worlds, big block grunt at 2800-3200 like a 455 Stage 1 buick....but still have top end power and rev capacity of a hemi

Build it with a mild 238-242 ish @ .050 cam and you'll find more reasons you'll want to go drive it, as opposed to making excuses NOT to.

THATS the answer I was expecting.

Can you still use the stock oil pan, pickup tube and windage tray with this setup?

Yes you can but I 100% recommend you go with the 2.200" BBC sized rod journals as it typically gives you even better crank to rod clearance around the bottom of the bores than the typical 4.15 stroke/2.325" journals and a 7.100" rod will lighten the pistons up quite a bit as well.

Hemi's already have the 1/2" pick up so the only thing you might need to do is clean-up/smooth the casting around the pick-up tube where the pick-up threads into the block.

Dang- could not be stated better.

I am a believer in “The wisdom of Moparts.”

Concerning “state of the art” of piston crown design,
what is the ideal replacement piston design for a stock stroke 426 Hemi
designed to not just survive,
but optimize 91 pump gasoline?

So much has been discovered since street 426 Hemis were sold to the public.

What 3 people still alive qualify as
“highly knowledgeable and bluntly honest”
about the 426 combustion chamber
and the shape its floor should be?

I built my wedge that way. 9:1, 500 hp, 600 ft/lbs on 87 regular and more than enough bottom end torque to launch a 4800 lb New Yorker around with authority with 3.23 gears. 4.15 stroke.

He said it's a street car and it sounds like he drives it further than the local Dairy Queen. I'd build a 9:1 4.25 stroke tractor motor with a power brake friendly cam profile and enjoy the no drama able to drive it cross country street manners that can still roast tires or dust a 911 on a 60 mph roll on.

Kevin

If you are going to be a bear, why not be a grizzly? I'd stroke that Hemi, get a minor port job on the heads, 3/4 roller cam, 10.5:1 compression.

Look, the 425-460 horse of a stock Hemi was a big deal in 1966-1967. Today, it's nothing. Don't embarrass the Hemi legend by building an engine that won't keep up with the LS.

The factor of embarrassment is based on the stroke?

If so I'll put 10k up against this car heads up no matter what displacement it ends up at.