kingkong Posted October 31, 2008 Report Share Posted October 31, 2008 i have 421 cheetah cub that im thinking about upgrading to a 7 or 10 mil. my question is can i keep the cylinders 68mm and just change the crank. Quote Link to comment Share on other sites More sharing options...
Blewbyu Posted October 31, 2008 Report Share Posted October 31, 2008 Nope, The 4mill cub is a different cast then the 7 or 10mills. Youll have to sell yours and get one for the one you choose. If you had a 7 and wanted to go to a 10 you could. But not 4-10. Plus the obvious trenching of the cases. Quote Link to comment Share on other sites More sharing options...
firebanshee Posted October 31, 2008 Report Share Posted October 31, 2008 I think that if you are going to a 10 mill you should go away from the cub cylinder and go to a cylinder that uses bigger reeds because the reeds on a cub cylinder are about max out with a 4 mill stroke. Quote Link to comment Share on other sites More sharing options...
kawiking Posted October 31, 2008 Report Share Posted October 31, 2008 I think that if you are going to a 10 mill you should go away from the cub cylinder and go to a cylinder that uses bigger reeds because the reeds on a cub cylinder are about max out with a 4 mill stroke. ?????? what ????? Quote Link to comment Share on other sites More sharing options...
firebanshee Posted October 31, 2008 Report Share Posted October 31, 2008 ?????? what ????? I have been told by a couple of reputable motor builders that if i wanted to go 10 mill that i should use a dm or twister cylinder or one that uses a 250r style reed cages. I currently run a 4 mill cub on alky and have been making plans to go 10 mill and wanted to use cub cylinders and have been told that i should consider a different cylinder to get the most power. Quote Link to comment Share on other sites More sharing options...
shanYE west Posted October 31, 2008 Report Share Posted October 31, 2008 I think the stock reed cages work fine on the 10mil cub.. LOTS of strong running 10mil cubs... Do I think the reed cages are a limiting factor.. yes... but you also have to weigh the cost/power ratio.. To upgrade to a DM the price difference is HUGE compared to a cub... and Yes you get more power.. but you pay for it... buck for buck.. the 10mil cub is VERY hard to beat.... Quote Link to comment Share on other sites More sharing options...
dajogejr Posted October 31, 2008 Report Share Posted October 31, 2008 I've seen plenty of 10 mil cubs run right with 10 mil Cheetahs, which have the bigger intakes and bigger pistons.... Yep...DM should be faster, but as said, big cost difference. Quote Link to comment Share on other sites More sharing options...
shanYE west Posted October 31, 2008 Report Share Posted October 31, 2008 I've seen plenty of 10 mil cubs run right with 10 mil Cheetahs, which have the bigger intakes and bigger pistons.... Yep...DM should be faster, but as said, big cost difference. Yep.. LOTS of hard running 10mil cubs. its tried and proven. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted October 31, 2008 Report Share Posted October 31, 2008 The difference in the power of the Twister or DM compared to a Cub is because the bore is huge (72-78mm) on those, yielding much more ccs. I wouldn't base my decision to go with those based on reed cage design, but on whether I want a 465 cc (or whatever) or a ~ 600 cc motor; and what my chassis could handle....and what classes it would fit in at the track. .........And of course price. But that would be the last determining factor in drag racing :biggrin: Quote Link to comment Share on other sites More sharing options...
dajogejr Posted October 31, 2008 Report Share Posted October 31, 2008 You will need some additional porting when it comes to the Twister. It does not run as good out of the box or "cleaned up" as a cub.... Quote Link to comment Share on other sites More sharing options...
KaosBanshee44 Posted October 31, 2008 Report Share Posted October 31, 2008 You can sell that stuff man and get a good amount of money to put down on some 10mill parts. If you decide to do the upgrade i suggest breaking that motor down soon so you can send off the cases to get trenched. use that time to sell parts and buy new parts. I know a great guy to get parts from his name is Dave...haha I'll help ya out man PS this guy lives about 20min from my house Quote Link to comment Share on other sites More sharing options...
firebanshee Posted November 1, 2008 Report Share Posted November 1, 2008 I definatly agree that there are alot of strong running 10 mill cubs out there i have gotten beaten by some of them but i guess the point i was trying to make was if you set up your 4mill properly that it will run right with the 10mills or beat them. So i had it explained to me best when i wanted to up grade to a 10mill cub that i should save my money until i can buy something that will way out perform what i have allready gotten, he told me that he would gladly take my money and help me upgrade to a 10mill cub but i should wait and buy something that would beat the 10mill cub and the 4mill cub which makes sence to me because if i sold all my 4mill cub stuff and went 10 mill cub and then a 4mill cub came along and beat my 10mill cub i wouldnt be very happy so in my case i think i will wait and save my money like they always say you have to pay to play hahahah. Quote Link to comment Share on other sites More sharing options...
shanYE west Posted November 1, 2008 Report Share Posted November 1, 2008 10mil cubs on average make about 10hp more then a 421cub.. That being said... a properly setup/tuned 10mil cub will always have the mechanical advantage over the 421 cub. Price to upgrade to a 10mil from a 4mil is around $1500 Price to upgrade to a DM from a 4mil cub is about $4-5k Buck for buck... you can't beat the 10mil cub.. on our tracks here its a 3.9 motor out of the box. I've yet to see a any 421 go 3.9's or even 4.0's out of the box. Quote Link to comment Share on other sites More sharing options...
firebanshee Posted November 1, 2008 Report Share Posted November 1, 2008 10mil cubs on average make about 10hp more then a 421cub.. That being said... a properly setup/tuned 10mil cub will always have the mechanical advantage over the 421 cub. Price to upgrade to a 10mil from a 4mil is around $1500 Price to upgrade to a DM from a 4mil cub is about $4-5k Buck for buck... you can't beat the 10mil cub.. on our tracks here its a 3.9 motor out of the box. I've yet to see a any 421 go 3.9's or even 4.0's out of the box. How do you think a 4 mil super cub compares to a 10mil cub ? Quote Link to comment Share on other sites More sharing options...
shanYE west Posted November 1, 2008 Report Share Posted November 1, 2008 4mil supers make about 3-5 more hp over a 421 cub (depending on builder)... but the super cubs do require porting and actually make less power then the 421 cubs out of the box unless their ported. If I was upgrading from a 421 cub.. I'd go for the 10mil still. The super cub would be a good option if you were starting a build and needed a head and planned on having port work done anyways. Quote Link to comment Share on other sites More sharing options...
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