3.4 Whipple & crank snout issues

[Wings65288]

Have been doing a lot of searching on this and thought I'd make a new thread. More people have done the swap and new info is out there so figured why not.

I'm thinking of putting a 3.4 Whipple on. I have a metco 4 pound lower with an upgraded T56. McCleod single disc clutch. Stock belt tensioner.

I'm reading it's the high RPM gear changes the put that violent tug on the snout thus snapping them. That's why I hear auto is the way to go if possible.

Who here has broken lower crank pulleys and crank snouts, who here has NOT? What do you have done?

 

[GodStang]

Have been doing a lot of searching on this and thought I'd make a new thread. More people have done the swap and new info is out there so figured why not.

I'm thinking of putting a 3.4 Whipple on. I have a metco 4 pound lower with an upgraded T56. McCleod single disc clutch. Stock belt tensioner.

I'm reading it's the high RPM gear changes the put that violent tug on the snout thus snapping them. That's why I hear auto is the way to go if possible.

Who here has broken lower crank pulleys and crank snouts, who here has NOT? What do you have done?

I have a Kenne Bell 3.6LC and have not broken mine. I know many many many that have 3.4Ls and have not broken theirs on basic stock setups. Keeping the lower cage helps. Also most of the people that have broken pulleys or lowers are racers and have their cars at the track every weekend.

On Modfords there is a whole discussion about keying they crank to help.

 

[Wings65288]

I feel better already. Lol no jk, do you think going to a Metco -2 (6.55") lower would help? I don't have a caged lower but if it's that important I'll be in the market for one. I hear guys breaking caged lowers too tho

 

[badmpg03]

I read a lot of Malcolmv8's threads back when, believe he broke several with his issues but with the 2.9 not 3.4
Alot of it is boost level and how hard you are spinning

My shop in Houston has been working on Cobra's for 16 years and they said some of the same that breaking snouts with 3.4 was not a frequent thing but at same time it was not a surprising event and it happens. I went with the 2.9 bc of this.

Are you on stock internals? What are your thoughts on the gen 4 2.9?

 

[Wings65288]

I've got a E85 Teksid build with Gibtec 9.5:1's. The crank is stock, ARP studs on both the mains and heads. The reason I'm going with this 3.4 is a buddy is giving be a really nice deal on it. I'm thinking if I get a caged lower and replace the bushings with these Schedule 80 from mcmaster.com (per Malcolm the legend himself) I HOPE to be fine. Ill run a 3.5" upper and that SHOULD put me at about 23 pounds of boost.

I'm really just trying to set myself up for success with this thing. Nothing's guaranteed but I'm gonna try and play it safe as possible.

 

[03 Cobra DSG]

I have a 3.4 and have not had any issues. Only at 19lbs currently but going to be running around 22-23 soon.


Sent from my iPhone using svtperformance.com

 

[Blown38]

We have a 3.4 on the Marauder. No problems. Have the 6.55 underdrive pulley on the crank and 3.5 on the blower. Spin it to 7k all the time with 2 step on the line and many rev limiters at the stripe. Knocking on wood now

Made 25psi mufflers were real small. Put a bigger exhaust on but haven't been to the 1/4 mile yet. The 8th mile shows it dropped about 1.5psi with the new exhaust.

 

[b00sted4v]

No issues here, running 3.4 Whipple with 3.5 sc pulley with stock crank pulley, Thump RRR tensioner and 100mm idler. Cars making 814whp/783wtq @ 24.3psi