High RPM diff. between 300 drag and 260

[STVBOY]

Just curious what internal parts are different in the 300 drag vs the 260. I am assuming pistons are one but what about the crank and rods? On my 260 now I see just shy of 9000 rpm and would like to drop down a prop but afraid I might have a timebomb on my hands. I know 300 drags twist over 10,000 rpm and can live for quite along time. Just want to know what I need to make it live above 9000 rpm. Thanks John

[us1]

The internal parts are all the same, just the port heights are different and the exhaust chest and
heads. On the outside the EFI box and fuel regulator are also different.

[Raceman]

Are you drag racin' or otherwise concerned only with acceleration? If you're just runnin' it on a lake why do you want to turn it harder? If you're turning it 9K now the boat will run faster on top if you add pitch rather than takin' it off.

[STVBOY]

Thanks US1

I just wasn't sure why a drag can last for so long at 10,000 plus? So you think twisting over 9000 rpm for short burst should be okay then?

Raceman yea I don't really care that much on the top end as I do the acceleration of the boat. Mainly just on the river with v drives and jets.

[us1]

It will last just as long as a drag at 9000 RPM. I do know though that anything over 8000
seriously shortens the life of the motor.

[Jay Smith]

The Drags come stock with single ring pistons , 1" spacer plate
( intake area ), 175 lbs compression heads ( 26 CC's on the stock Drag verses the 260 38 CC's) , the tuner adapter perch is machined down 3/4 " more than the 260, the tuner is shorter and staggered ( 1 3/4" shorter on the starbord side ) since 2000 the drag motors also have the 50 series rods
( larger ) the larger 50 series rods were on the 260 with Mahle pistons but were retrofitted with Weisco pistons and the 41 series rods in late 1994, that is what was on them until the 280 replaced it till present, since 2002 the Drags are retrofit wit a special Brucato SVS intake that replaced the horn and a A13 brain when the SVS is used the 1" spacer were removed... Somewhere around 2002 Weisco came out with the two ring top locater pinned piston to replace the pitifull side pinned junk for the 260-280 and the new top pinned one ringer for the Drag motor..Also the 2004 models have the 50 series rods that have been lightened via CNC cuts but are .100" more narrow on the top bearing area to fit the Weisco with the thin spacer washers and have lighter wrist pins . The 2004 have a more generous chamfer on the exhaust ports ( higher and more agressive angles , about .050" ) the stock 260 has about a 1" .565" port under the port to the top of the deck , the drag is around 1".535 "also the drag uses a 44 series head gasket because the piston on a drag is .004" out of the deck the 260 can use the thin gasket because its piston is .004" in the deck ! If you are turning the drag up to max
( 10,800- 11,000 rpms ) and it hasben fitted with the thin gasket the rod can streach and kiss the piston to the head , the new drag has a new "O" ringed head with an additional water flow from the heads to the top of the block ! The ECU's on the Drags are rather special and are made for all out acceleration and are quite lean in the mid range ! They are not for the everyday crusier and are lean if the user holds the motor at 5500 or so. The first Drag motor ECU was an A-48 and was a very forgiving brain ( rich ) and a low pressure Gold regulatered unit 40 lbs ! The next generation was the A-63, the motorolia A-6 and now the new A-13 ( SVS model ) are all now all high pressure 56lbs units with larger fuel pumps........

I think thats it !

[Hot Shot Merc]

Your makeing me drewl.I want a new drag:D

[MikeM]

Well said hot shot merc. I am glad Jay Smith and others understand this stuff because I don't. I sure like reading all this technical stuff and I need a bib also.

[STVBOY]

Thanks Jay/John

My motor is a stock 260 with 31cc heads, SVS, a48 chip and a one piece adapter with a G force tuner. I know the drag makes alot more power due to the port timing and porting but they can turn 10000+ without putting a whole throught the side of the block. I just wanted to make sure my rods and pistons could withstand over 9000 rpm for short bursts. I turn a 24p just under 9k and want to run a 22p. Is 32:1 sufficient for oil or should I go more?

Thanks JOhn

[Firestarter]

Great post Jay, the only thing is I had some two ring top pins in a 99 drag, and saw a set sometime before that...... but with all the changes I can imagine it is all starting to bluuuuuuuuur.

RT

[Techno]

Just how much longer can a drag run at 10 grand than its neighbor? I mean are we talking seconds, minutes or days?

How many runs can one make on the drag circuit before rebuild? Again is it days or seasons?

I thought the drag was a power element not a time item. I mean tenths of seconds of ET and not how long you can run it.
If you can afford to buy one and run it in drag racing then you can afford its upkeep too?