Stroking G-Body Motors

84dragcutlass

Royal Smart Person
Supporting Member
Aug 20, 2009
1,014
113
North Vernon IN
Watched that episode, it was a good one. I think the point that needs made here is that while i dont think anyone is deliberately dogging you for your idea the customer base for one probably isnt there and the engines themselves are probably at the stage where its just an accident waiting to happen. Ill make some points to these just to elaborate. Again not dogging your idea its good to have people on the forum coming up with things for our cars.

#1 customer base: Without plenty of people to buy the return on investment isnt going to be all that great and as seen here so far most people wouldn't put that much effort into initially stroking an engine that came from the factory as weak in as many areas as these did without doing a full on redo of the engine. The majority of these cars arent in the hands of teens looking to swap in a set of headers anymore, that has moved on to imports, early 2000's Fbodys and others for the most part. So the majority of people looking for upgrades are doing so with a much more "start from scratch" or "non original" point of view.

#2 engine stages: the engines in most of our cars are not stock, and finding an all original example is getting harder and harder to do so the ones that are still stock era correct examples the owners probably wont be interested much in doing a stroker engine. With the price of Jegs and the like being so low on already built stroker engines that throws a wrench in the plan as well. Even if the select few would go to the trouble of doing the modification then the result is getting obvious. They are going to kick the rods right out of that thing, as has been said in earlier post the pistons are outdated, weak, and so are the rods. Add that to 30+ years of fatigue and lord knows what kind of lack of maintenance by Grandma Smith going back and forth to church before the mullet marauder bought it from her to drive daily like Earnhardt on a backroad. So what you are going to have is an owner who now has a "stroker motor" that will not only have high expectations for HP and will be sadly let down by the results but also an owner who now thinks they have a high winding race engine that will be heading for the scrap yard faster then that rod came out of the side of the block. The vast majority of people will either start with a factory roller cam block, bore and stroke it and build it themselves or buy an already built engine from Jegs or the like for a fraction of what it used to cost 10 years ago and throw it in there car and call it a day. IF that car already hasn't had all of this done in the past 30+ years anyway. If your idea truly works it might be best applied to a newer car that is coming into fashion with teens looking for a budget car for school and back, just an idea no hate what so ever.
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
2,481
113
Upstate NY
Changes in rod length have a purpose and a couple of positive side affects. None of which are more HP and more low end torque without any additional cubes. But more torque than a shorter rod engine of the same displacement it can produce is definitely valuable if you're willing to spin the prerequisite additional rpm's. Also much less stress on the block and main bearings is another benefit of larger rod to stroke ratio. The largest benefit, IMHO, is when an extra atmosphere or two of pressure is added (can you say BOOST).

After that though, it's all down hill in NA world.
 

joesregalproject

Comic Book Super Hero
Nov 4, 2012
4,828
113
Pittsburgh, PA
changing rod length and stroke was minimal

Me trying to keep my mind out of the gutter-
DQT63W_UQAU225I.jpg
 

5spdCab

G-Body Guru
Dec 29, 2019
860
93
Tukwila, Wa.
After 6-1/2 pages of "it'll never work", and "you're wasting your time", vs, "I have an idea that I think will work and be affordable for the average guy", maybe hear him out, and see how he proposes to make it happen. After all, everything was impossible until someone finally did it. As far as those sceptical because he hasn't given details of how he plans to accomplish this feat, when you are working on obtaining a patent for something, the details are always TOP SECRET until the patent is granted.
I don't see anybody being wrong here, but, I think many people have missed the point of what he was saying. If I understand correctly, he wants to start with the foundation (however big or small), then add as time/funds permit. Starting with the block/internals, add improved exhaust down the road when funds permit, then heads/intake when funds again permit, and boost later if desired, and funds permit, all the while keeping it as a usable vehicle.
Just my two cents.
Hey Max, you go buddy! Good luck.
 

DRIVEN

Geezer
Apr 25, 2009
7,010
113
*CENSORED*
I'm actually intrigued by the claim because I'm just not smart enough to figure out how to make a longer stroke crank fit stock block, rods and pistons. Respectfully, so far this whole thread has looked like a 7 page troll post because it started with a vague claim with no details followed up with, "So, if you would be so kind, read, think ask." Well, many have done that. Still no details. Another odd angle is that it's unlikely that most guys would opt to change the one part that requires an engine removal and complete disassembly as a "starter mod". It's kind of the opposite of what the last 100 years of hotrodding has been.
But hey, maybe this that one huge game-changer. I'll be waiting for that documented prototype installation.
 

Max Headroom

Master Mechanic
Thread starter
Sep 8, 2011
369
63
Explain to me how this significantly improves the Volumetric Efficiency of this otherwise gutless engine? Making the internal size of the pump larger does not directly translate to better pump performance if it is rife with restrictions on the intake and/or exhaust side.

Porting the heads, adding a cam with more duration, exhaust scavenging, these things make the difference in air pump performance.

Have I pissed you off, or do you just not listen. Where in all of my posts did I mention Volumetric Efficiency?? I said I was working on a way to increase stroke with just a crank change and the addition of a kit I am trying to work the kinks out of.

So let's just say that you don't change the crank but you want to improve performance of the low compression, open chamber head engine that you already have in the car. What would you do?? Port the heads, add a cam with more duration and as much lift as the heads could accept. Change exhaust to something that would scavenge better. Upgrade to a better carb.

Wow!! That's just what I would do after changing the crank, EXCEPT that my low compression engine would have higher compression (because of the stroke change and the addition of the kit) and would have more cubic inches which would offset some of the deficit of the open chamber heads. All of the exact same changes you want to make would work even better on the engine after adding the stroker crank. Just like you, I know a couple of things about making more power.

You are missing the whole point of why I am interested in doing this. Try to remember when you had a car and no money. How did you make improvements?? You bought, begged or stole whatever performance improving parts you could find and then installed (or tried to) them yourself. Working under the hood all weekend was worth it if you could get any improvement at all. I remember it and have always wanted to find ways to make it easier on the guys who are coming after us. What I am working on now may or may not have as wide an application as I would like but I have no way of knowing that without communicating with people like the ones on this forum. Because of the cars we like, we almost all start with under performing GM engines of all types. I know sbc. It's almost the only thing I've ever worked on and I know it will work for that. I am hoping to make it more cost effective for others starting out with a car and no money.
 

Max Headroom

Master Mechanic
Thread starter
Sep 8, 2011
369
63
While I am curious as to how you plan on doing this by only replacing a crank IMO anyone willing to spend the money on a new stroker crank and your kit just so they can install this in a used engine (and in our cars who knows if you even have actual mileage) would most likely just spend the extra money and get an actual balanced rotating assembly that they will install in a freshly machined block that has been bored and honed and now will have stronger rods, new rings and bearings along with new pistons that are designed with clearance for the stroker crank.
The conventional way of stroking an engine has worked well for a long time and appears to still be growing strong so it might be hard to gage interest when you are not willing to give out a single detail and your Guinea pig engine is a SBC, probably the most commonly stroked engine ever, conventionally at least.
So those are my thoughts, others will vary.


You have never started to make improvements to the clapped out POS engine that came in your car? You always had enough money to buy all new and pay for machining? If so, then I am obviously not talking to you. I mean that with no offense. I still have to save for some of the things I want to do to my ride. Who is going to pay for all that new sh*t and the machining, etc. What about the guy who put everything he had into just buying the car. Where does he crap the money for what you list above? How long does it take? I bet he can save enough to pick just a crank long before he can save enough to do everything on your list. If money is not an issue, then by all means, do it your way.
 

Cauterize

Greasemonkey
Feb 9, 2019
147
63
You have never started to make improvements to the clapped out POS engine that came in your car?
No. I left what I had in the car. I did nothing other than preventative maintenance and drove it for years the way it was. Find a good cheap engine, used parts ect. as one should. I scrounged together my entire drive train for less than 250 dollars
No amount of polish will ever change the fact your turd... is a turd.
 

Similar threads

G-Body Performance Upgrades

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck ConsolesDixie Restoration DepotMike's MontesP-S-TSouthside Machine PerformanceUMI Performance

contactAdmin@GBodyForum.comfor info on becoming a sponsor