200FF or 225 Promax to mod?

[LakeFever]

I spent a ton of time trying to find the differences between an FF and a 225 promax. What i discovered is the FF appears to be the same basic casting and likely has the same transfer ports. The differences in power are; the size of the exhaust dump. The promax has the large rectangle where the FF is smaller and square. Easy solve with a die grinder. The promax also has opened up rod slots although not as huge as a 260. Also an easy mod with a die grinder. The promax has higher compression. Easy solve with a quick skim on a mill. The promax comes 7 petal reed vs the FF which comes 4 petal. Then theres the brain which is specific to the 225 promax. I believe there are three different variants of the brain, two for sure. There was an issue with the very early brains being curved lean or something like that. Later versions not an issue.


Far as i can tell thats all there is. Some reputable builders claim the transfer ports are indeed different but others say not. Either way a well prepped FF surely will get up in the 260 range. Seems rpm is the main issue with the steel sleeves. Running 7500+ for long runs on the steel bores is where the nic becomes a necessity.

hope this info helps you out. Id consider an EE too without blinking. Unless the transfer ports are different than an FF you should be able to mod one of these the same


*edit* how did i jump to post one while replying to Stoneman? Weird. The first post is below

[tlwjkw]

what are ya gonna do with tha rig?.. what kinda boat???... operational (fuel etc.) cost a mater??? 8 grand (rpm) or less motor or closer ta 10???

posting sequence is acting stupid???

[25two.stroke]

Sequence is backwards for me too. And it said I had to wait 10237 seconds to post even though I haven't lately. Promax is small bearing fyi

[stoneman]

I've been thinking about this for a some time! About building a Hi-Performance steel bore motor. I know that some of you have been doing this for a while and I need some insight into the best way to go?

Would a 260 front half work well with a 225 Promax block? Which front half would I need? Does a 225 Promax use a Big bearing crank or a small bearing?

What about the 200 FF motors? Same questions as above? I'm good with spending the money on machine work and all of the best parts, I just want a motor that makes good HP and that will last for a good while between rebuilds.

With all things considered, would a 260 Front half and air horn give me the best bang for the buck over a slide intake or the Lazer injection when adding intake and exhaust porting? Probably run 150 psi compression.

Thanks in advance!
Stoney

[stoneman]

I would be running it on a STV Euro, I usually run a 30 Lighting et or 32 drag 4 prop. I'm going to want to turn 8000 to 8500 rpm with the promax. I've had 260's and 280's in the past just wanting to try something different.

[stoneman]

Thank you for taking the time to explain the differences! Great info...........! The 7 petal front half of the promax is a big plus in my opinion!!

I spent a ton of time trying to find the differences between an FF and a 225 promax. What i discovered is the FF appears to be the same basic casting and likely has the same transfer ports. The differences in power are; the size of the exhaust dump. The promax has the large rectangle where the FF is smaller and square. Easy solve with a die grinder. The promax also has opened up rod slots although not as huge as a 260. Also an easy mod with a die grinder. The promax has higher compression. Easy solve with a quick skim on a mill. The promax comes 7 petal reed vs the FF which comes 4 petal. Then theres the brain which is specific to the 225 promax. I believe there are three different variants of the brain, two for sure. There was an issue with the very early brains being curved lean or something like that. Later versions not an issue.


Far as i can tell thats all there is. Some reputable builders claim the transfer ports are indeed different but others say not. Either way a well prepped FF surely will get up in the 260 range. Seems rpm is the main issue with the steel sleeves. Running 7500+ for long runs on the steel bores is where the nic becomes a necessity.

hope this info helps you out. Id consider an EE too without blinking. Unless the transfer ports are different than an FF you should be able to mod one of these the same


*edit* how did i jump to post one while replying to Stoneman? Weird. The first post is below

[LakeFever]

Thank you for taking the time to explain the differences! Great info...........! The 7 petal front half of the promax is a big plus in my opinion!!

From what i have read above 7000 rpm the seven petal starts to shine and make solid gains. Ive never had a seven petal nor spun one that high so im tapped out. RJ bought an allison with a well prepped James Perry 2.5 FF i wonder how high he turned it? Come to think of it Perry does a lot of these hot mod fishin block builds you should get his thoughts too. Helpful guy

[tlwjkw]

From what i have read above 7000 rpm the seven petal starts to shine and make solid gains. Ive never had a seven petal nor spun one that high so im tapped out. RJ bought an allison with a well prepped James Perry 2.5 FF i wonder how high he turned it? Come to think of it Perry does a lot of these hot mod fishin block builds you should get his thoughts too. Helpful guy

agree.. give Perry a call.. seems like he has become a VERY reputable machinist/motor builder..............

[Mrzip]

A lot of people have had great success cutting a steel sleave motor. Drag specs. Don't know of one unhappy person.

[LakeFever]

Forbesauto built a mean steel sleeve motor and posted up a lot of pics of his mods in one of his threads. Theres also this thread which covers a lot of chest work

https://www.screamandfly.com/showthr...ust-chest-mods

[stoneman]

That's some great stuff in that thread!!! I reached out to one of the main guy's posting there! I also looked up James Perry and will reach out to him soon!!
Thanks for the link!! It's awesome info!!

[rgsauger]

James Perry did some 2.4 work for me a while back when I melted a cylinder. VERY pleased with his work! First quality. 423-304-0930. He's down near Chattanooga, TN.