pipe for a 98 740 unionbay motor in rev chassis!!

[Thunderguy BOOSTED]

Hey!!

Iam going to build another little 740 UB, but this time iam going to through it in a rev chassis!!

What should i do for pipe(s)? I know there going to have to be custom pipes but just wanted to see if anyone here has done it with a 670/740??


Thanks

Justin

 

[TT670]

Kinda apples and oranges in engine design but I did an RKT 734 in the REV chassis and took a few pipes to Dynotech for testing, this was back in late 2004 so I dont remember the numbers. A dynoport 600HO pipe made the best power followed closely by a stock 600HO pipe. A stock 800 pipe was down significantly in power compared to the others and went straight to the spare parts bin. The best power, and the route I took came from a stock 600HO pipe with a sleeved insert in the stinger made from .020ga sheetmetal, so it was obviously not a long WOT pull setup. FYI this was done at about 1500ft elev.

 

[Thunderguy BOOSTED]

Kinda apples and oranges in engine design but I did an RKT 734 in the REV chassis and took a few pipes to Dynotech for testing, this was back in late 2004 so I dont remember the numbers. A dynoport 600HO pipe made the best power followed closely by a stock 600HO pipe. A stock 800 pipe was down significantly in power compared to the others and went straight to the spare parts bin. The best power, and the route I took came from a stock 600HO pipe with a sleeved insert in the stinger made from .020ga sheetmetal, so it was obviously not a long WOT pull setup. FYI this was done at about 1500ft elev.

Thanks for the info!!
do you remember what you were making for HP on that engine????

thanks

Ps this is what the guy with the twin pipes said: "I wouldn't worry too much about actually hp but more on clutching and jetting. If I could do it again I'd run an 800 stock pipe and npp can on my 740. I'll sell you the pipes I'm runnin if ya like. I just built a 670 in a rev and used a stock y pipe with an 800 flange welded on with a 600 pipe and some cane I got out of the shop garbage! Goes like stink. So I guess the performance and reliability is more my concern than actual hp numbers."\

Thunderguy BOOSTED

 

[TT670]

I dont recall exact numbers but once it was all sorted out it was 140ish. I didnt run it long, mid season after putting the 734 together the recoil starter came apart, wedged a piece of plastic between the flywheel and case and busted the mag end right off the case. I ended up selling the 734 top end, stuck a 700 in the sled and sold it. I kinda agree on the twin pipes, I never did a UB740 but my last 670 was a fully ported crankshop engine, it was a much more consistent, enjoyable sled to ride with a single compared to twins. No doubt folks can make the twins work, it boils down to ride time vs wrench time for me.

 

[Thunderguy BOOSTED]

I dont recall exact numbers but once it was all sorted out it was 140ish. I didnt run it long, mid season after putting the 734 together the recoil starter came apart, wedged a piece of plastic between the flywheel and case and busted the mag end right off the case. I ended up selling the 734 top end, stuck a 700 in the sled and sold it. I kinda agree on the twin pipes, I never did a UB740 but my last 670 was a fully ported crankshop engine, it was a much more consistent, enjoyable sled to ride with a single compared to twins. No doubt folks can make the twins work, it boils down to ride time vs wrench time for me.

YA!!

Well my 97 740 UB motor with twin crank shop pipes in a 97 summit chassis is the best motor i have owned!!
U never have to worry about the jetting!! Like when we ride, we start at 4300 feet and ride to 9000 feet, i dont have to look at my jetting one time!!
(i have no HAC or vari-flow) and iam running 360 mains( could drop down to a 350 mains and make it run even better up higher!!!

but any way....

 

[chrispy]

Where are you riding at 9000' near Williams Lake?

 

[Thunderguy BOOSTED]

Where are you riding at 9000' near Williams Lake?

Taseko Lake! 2 and a half hours South west of Willys puddle!! well the highest mountain out here is mtn Taseko thats at 10,000 feet!! (BUT ITS A PAIN IN THE A$$ TO GET UP THERE IF U EVEN CAN)

 

[TT670]

I dont recall exact numbers but once it was all sorted out it was 140ish. I didnt run it long, mid season after putting the 734 together the recoil starter came apart, wedged a piece of plastic between the flywheel and case and busted the mag end right off the case. I ended up selling the 734 top end, stuck a 700 in the sled and sold it.