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3G Hemi - valvetrain & other questions at 8000+ rpm? #1491693
08/27/13 05:20 PM
08/27/13 05:20 PM
Joined: May 2005
Posts: 723
Houston Tx
Uhcoog1 Offline OP
super stock
Uhcoog1  Offline OP
super stock

Joined: May 2005
Posts: 723
Houston Tx
I've been toying with the idea of throwing a bigger cam in my forged 5.7 and moving the powerband up a bit. I need to know what I can get away with (how much RPM I can get away with).

currently:
218/224 on 113.5 + 3*
lobes are both XFI exhaust lobes - 3034 intake, 3035 exhaust
PAC 1518 springs, titanium retainers, 6.1 pushrods, heads are milled .020 or .030

On the dyno I pulled it to 7,000 rpm. That's about all she had. I'd love to find an option that let me shift at 8,000+ rpm (with just a spring and cam swap)

With a moderate cam lobe, what rpm could be possible with factory rockers, a single beehive (PAC 1518 or similar), and custom length or 6.1 pushrods?

*I understand a number of drag pak guys are shifting at 8,400/8,500 rpm. Any info on what they're doing to get the RPM would be appreciated.

**This car will be used for non-competitive road racing. This cam is probably about right for now, but I'd like to put something bigger in the future. I'll need to keep the lobe profile fairly mild to survive what I'm doing, which should also help keep the valvetrain under control for higher RPM, yes?

Also- what else should I be worried about at 8,000+ rpm on the 3G hemi's?


Motor:
5.7 block, Wiseco +23cc dome pistons, K1 rods, 6.1 crank. Ring gaps .020 & .024
FRI 'extreme' 5.7 heads. flow upwards of 350 cfm intake. Ferrea 2.02/1.60 valves. Titanium retainers.
Hilborn intake
unequal length mid length headers welded by me - around PS box - not the best flow no doubt. 3" x pipe, mufflers, dumped at axle.
tko600 5 speed manual
ford 9" floater
Megasquirt 3x engine management


-'02 Dodge Viper Ex-World Challenge racecar
-'73 Duster, 6.1 based 392 hilborn hemi, tko600, full floater rear 9", Hellwig custom bars, viper brakes, built for road course
Re: 3G Hemi - valvetrain & other questions at 8000+ rpm? [Re: Uhcoog1] #1491694
08/27/13 10:37 PM
08/27/13 10:37 PM
Joined: Jan 2003
Posts: 344
Burlington, Ontario Canada
Dave_S Offline
enthusiast
Dave_S  Offline
enthusiast

Joined: Jan 2003
Posts: 344
Burlington, Ontario Canada
Hi Wade

Put a turbo on it!!!


Dave Stillie
'73 Swinger
5.7 Hemi, 88mm turbo, powerglide, cal-tracs & 8 3/4
Mega-Squirt EFI
[email]8.93@149
[/email]
Re: 3G Hemi - valvetrain & other questions at 8000+ rpm? [Re: Dave_S] #1491695
08/27/13 10:44 PM
08/27/13 10:44 PM
Joined: May 2005
Posts: 1,130
Dayton, Ohio
W
wldtm Offline
super stock
wldtm  Offline
super stock
W

Joined: May 2005
Posts: 1,130
Dayton, Ohio
Besides the engine have you had the hemi behind the tko? It is faceplated or set up for shift above 6k rpm?

The reason I ask is that trans stock is not favorable from high rpm shifts. It maybe set up for it, but if not, I think shifting at 7k would be hard with that trans.

Either way the car is a neat build.

Justin


Interested in having you car wired? Drag car, street car, EFI swap? PM for details
Re: 3G Hemi - valvetrain & other questions at 8000+ rpm? [Re: wldtm] #1491696
08/27/13 11:58 PM
08/27/13 11:58 PM
Joined: May 2005
Posts: 723
Houston Tx
Uhcoog1 Offline OP
super stock
Uhcoog1  Offline OP
super stock

Joined: May 2005
Posts: 723
Houston Tx
Dave! How's the project coming? When do you expect to get it out to the track? Can't wait to see what she does!!

Justin- I have not had trouble shifting this transmission at 7000+. I'll know more after going to the strip and the Texas mile, but I don't anticipate any problems.


-'02 Dodge Viper Ex-World Challenge racecar
-'73 Duster, 6.1 based 392 hilborn hemi, tko600, full floater rear 9", Hellwig custom bars, viper brakes, built for road course
Re: 3G Hemi - valvetrain & other questions at 8000+ rpm? [Re: Uhcoog1] #1491697
08/28/13 07:07 PM
08/28/13 07:07 PM
Joined: Feb 2003
Posts: 3,998
GO BUCKS !!!!!!!
3
340RICK Offline
master
340RICK  Offline
master
3

Joined: Feb 2003
Posts: 3,998
GO BUCKS !!!!!!!
Quote:

I've been toying with the idea of throwing a bigger cam in my forged 5.7 and moving the powerband up a bit. I need to know what I can get away with (how much RPM I can get away with).

currently:
218/224 on 113.5 + 3*
lobes are both XFI exhaust lobes - 3034 intake, 3035 exhaust
PAC 1518 springs, titanium retainers, 6.1 pushrods, heads are milled .020 or .030

On the dyno I pulled it to 7,000 rpm. That's about all she had. I'd love to find an option that let me shift at 8,000+ rpm (with just a spring and cam swap)

With a moderate cam lobe, what rpm could be possible with factory rockers, a single beehive (PAC 1518 or similar), and custom length or 6.1 pushrods?

*I understand a number of drag pak guys are shifting at 8,400/8,500 rpm. Any info on what they're doing to get the RPM would be appreciated.

**This car will be used for non-competitive road racing. This cam is probably about right for now, but I'd like to put something bigger in the future. I'll need to keep the lobe profile fairly mild to survive what I'm doing, which should also help keep the valvetrain under control for higher RPM, yes?

Also- what else should I be worried about at 8,000+ rpm on the 3G hemi's?


Motor:
5.7 block, Wiseco +23cc dome pistons, K1 rods, 6.1 crank. Ring gaps .020 & .024
FRI 'extreme' 5.7 heads. flow upwards of 350 cfm intake. Ferrea 2.02/1.60 valves. Titanium retainers.
Hilborn intake
unequal length mid length headers welded by me - around PS box - not the best flow no doubt. 3" x pipe, mufflers, dumped at axle.
tko600 5 speed manual
ford 9" floater
Megasquirt 3x engine management






I say yes on the 8K......I have not been to 8K myself usually around 7500. My cam is a .400 lobe wit 266 and 270 at .050 duration. I have only added the Sharadon shaft hold downs with ARP bolts pac springs and manton 3/8 pushrods. I have few street miles and some 1/4 mile passes on iit took apart top end for inspection shows no signs of wear anywhere in valvetrain.


Re: 3G Hemi - valvetrain & other questions at 8000+ rpm? [Re: 340RICK] #1491698
08/28/13 11:24 PM
08/28/13 11:24 PM
Joined: May 2005
Posts: 723
Houston Tx
Uhcoog1 Offline OP
super stock
Uhcoog1  Offline OP
super stock

Joined: May 2005
Posts: 723
Houston Tx
Learned something new today- stock 6.1 crank being cross drilled doesn't like high rpm. I heard both 7,000 and 7,500 rpm when asking what the limit for a cross drilled stock crank is.

Any fixes other than a new crank? High volume oil pumps? Etc?


-'02 Dodge Viper Ex-World Challenge racecar
-'73 Duster, 6.1 based 392 hilborn hemi, tko600, full floater rear 9", Hellwig custom bars, viper brakes, built for road course






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