Has anybody heard of a stroker kit using a crank out of a 258 ci jeep?

 

Nope. The 300 is a stroked 240 and there is really not much room left if any and nothing to be gained except a severe lightening of the pocket book trying to stroke the 300 for no ROI.

 

A 258 has a 3.90 stroke, so your "stroker 300" would end up a 294. I didn't check the journal size or the length, but I think it would be a complete mismatch, even if you could get past that small shorter stroke detail.....

http://www.jeeptech.com/engine/amc258.html

 

FarmeRick,

Welcome to the forum!

Perhaps your question is based on something you have heard from the "Jeep" crowd. I recently read something about a 258 [4.2L] crank being used in the more modern 4.0L block to gain ~1/2" stroke. The article claimed a result of 4.7L in displacement.

 

The 300 uses a 4" Stroke and 4" bore to my knowledge

 

3.98" thank you! lol. if your really hellbent on stroking a 300 (why) clifford used to make a stroker kit, i dunno if they still do. one thing that is less costly than stroking a 300; improve head flow. if a properly p&p 240 head can net you about 25+ hp, what do you think lets say, a bunch of chopped LS1 heads tig welded together? huge flow to match a huge stroke. the ls1 is 5.7 liters and the 300 is 4.9. with similar head flow, you can now improve stroke. get it? got it? good.

the alumium head from classic inlines is gonna be kick ***!

also, if you look at a cam profile for a 300 and the same profile for a 302, the 4.9 profile is a slightly lower rpm than for a 302, the head dont flow! lol

 

I really do appreciate all of the information I received on my question. I guess I'll swap cam & lifters, install headers and possibly upgrade the efi throttlebody and eprom chip.

 

 

bore is 4" stroke is 3.98" ...

do not try to use a 240 head on a 300 EFI... from what i have seen that doesnt work so well

you gotta be pretty good with fab work to take two v8 ls1 heads and cut/weld them up to make 1 inline 6 head though... but it would make incredible improvement if you do it right...but a good P&P of the existing head will make the biggest bang for you buck on these things... while your in there do a 30* back-cut on all the valves to help them flow a bit better

these EFI 300s are not at all friendly to mods...even a slighlty agressive cam can **** on the stock ECU...the pre 95 trucks with Speed Density (SD) will only accept about 172 hp of about 17% gain over stock, considering it alreading around 150 hp there isnt much you can safely do to it without upgrading the ECU....that being said, if yours happens to be a 96 with the Mass Air Flow (MAF) setup you can get a fair bit more out of your engine without touching the ECU...

 

sorry to confuse, but i was (in my mind) simulating ls1 heads on the 300, just to state that when you increase head flow, numbers will follow

 

Somebody should just design a turbo for the 300.

 

yeah thats true...im not sure if it was the LS1 but i know this has been done, taking 2 v8 heads and making 1 inline 6 head, i do not know how well it worked though

its been done many, many, many times ... 300s have also been super chagerd...a turbo works better though, and its been done more with some pretty incredible results to back it up... id like to do this one day just for ****s

 

I think what Bill means is a kit you can buy already set up and ready to bolt on to the 300 EFI, or carb, instead of getting a Chevy 6.5 turbo and trying to fab it all up yourself. Also I think you can buy the LS1 mod heads from a guy at Fordsix.com, but there is a lot more work involved because you have to figure out how to feed it and make it poop(custom intake, and exhuast).

 

Wow I din't know that you could get 25+ hp from a ported 240 head, thats probably a pretty cost efficient hp upgrade. If you consider each hp is like $10(they have said that for some time so it's probably $15-$25 per 1 hp now with inflation and all), thats not a bad upgrade.

 

The two v8 heads that were used were actually 351 windsor heads. They had better flow than the 302 windsor based heads and the same bolt pattern as the 4.9. But as stated, it would require an extremely skilled welder and machinist to do this propery, and quite frankly in my opinion, not worth wat u gain out of it. Also, there have been a few guys turbocharging the big sixes. Theres a guy on youtube, he has an early seventies maverick with a 4.9. All he did was a stock rebuild of the motor, with a close to stock cam and internals, and used a 7.3 powerstroke turbo. Hes pushing i think 12-13 lbs of boost and runs low 11's and mid tens in the quarter mile. Hes been drivin it for a few years now with no issues. Hotrod magazine also did an article on the build i believe