Budlight 0 Posted March 3, 2022 I was just wondering if you could put a 500 top end kit on a 450 with out any modifications and if you could use the 450 head Share this post Link to post Share on other sites
jeepwm69 7,751 Posted March 3, 2022 It will not fit. The 2012-up 500 top end will bolt onto a 420, because the bottom end of those two motors is the same, but the 450 is already the bigger bore version of the 400 Foreman, so nothing stock that has more CC's will fit. You can swap a 400 Foreman head onto your 450, which has a smaller combustion chamber and will up your compression a bit, but other than that, no stock bolt ons for a 450. @Fishfiles can tell you about the big bore kit he has on his 450. 2 Share this post Link to post Share on other sites
Fishfiles 20,147 Posted March 3, 2022 The 450 Big Bore kit " use " to come from High Lifter , it is discontinued , it is a 450 jug machined to accept a 500 cylinder sleeve , then you need a custom piston and rings ----- as Jeep stated a 400 head on top a 450 or 450 Big Bore kit is a compression increase , the valves and ports are all the same on the 400/450 , the compression dome is smaller on the 400 1 Share this post Link to post Share on other sites
Budlight 0 Posted March 4, 2022 Thank you the 500 is going to be too big to fit in my 450 bottom end Share this post Link to post Share on other sites
toodeep 1,760 Posted March 4, 2022 I had a friend that had the thumper big bore and while it was impressive for the little gain it didn't help. A stock bore machine did the same thing with more reliability. Share this post Link to post Share on other sites
Fishfiles 20,147 Posted March 4, 2022 I agree the big bore kits are wasted money , best to keep it simple ----- there is no over size for the 450 big bore kit , and it is the same with most of the big bore kits , it is a one time deal , if you trash the piston or bore it is over with --- I am actually afraid to ride mine and would never do it again 1 Share this post Link to post Share on other sites
56Sierra 1,845 Posted March 4, 2022 Jeep and Fish, You two impress the daylights out of me sometimes. Most times actually. I have problems figuring out which socket fits which ratchet. 2 Share this post Link to post Share on other sites
jeepwm69 7,751 Posted March 4, 2022 5 hours ago, 56Sierra said: Jeep and Fish, You two impress the daylights out of me sometimes. Most times actually. I have problems figuring out which socket fits which ratchet. Ha, if you saw all the stuff I've screwed up over time figuring things out you wouldn't be so impressed. 1 Share this post Link to post Share on other sites
