how well does Porting an Eaton work?

[blk04cobra1]

Well, I'd say you're seeing about 11-12 pounds now that you ported your blower, then you'll throw 4-5 more pounds on top...yes, it'll be a difference, but again....i'd strongly suggest a custom tune, then check it with your wideband b/c you'll be gaining 15-20rwhp.

[Linn@Amazon]

we had a 275 upper with a 4 lb lower on our car with a ported Eaton..you may be looking at fuel system upgrades if you go with a lower with the pulley you have now.Id still get a good retune no matter what you decide to do

remember that having an upper and lower pulley combo is a ratio of the two pulleys when it comes to calculating the boost added.

[Linn@Amazon]

Originally Posted by Dave B.

is it a big noticable change?? Id think it would be a lower RPM high torque gain,,,??

the blower rpm debate rages on...some say that adding a lower pulley gives you more torque and other say blower rpm is blower rpm. since the 275 upper is the smallest pulley you can get on the snout without grinding the snout down you can only see as much boost as your car will make with it..we see 8-10 psi on a stock Eaton so depending on what your Eaton car makes you can see 5-6 added psi with a 275.. it makes sense that to add more boost you will have to add a lower crank pulley. this does 2 things..it gives you more surface for the belt to contact with because adding a crank pulley is bigger..this helps with belt slip which causes boost drop ...the more surface the belt has to contact with the less likely to see belt slip..when you do a combo it is a ratio of the two..an after market boost gauge is a must with these cars if you are adding more boost...your car willmake what is makes with the combos and each car is different...by adding a crank pulley you will see torque come on sooner in the rpm bands and stay longer..is this giving you more torque? only where you need it to move a heavy car down the track or on the street..we have data from hundres and hundres of combo cars because we have specilized in the 03/04 Cobras and have worked exclusively with them since 2002 when they became available for reasearch and development.

[Big T]

Lynn, what type of power/torque would a 2.75 upper and a 2# or 4# lower put down in your estimation? Also would a 2.75 upper pair better with a 2# or a 4# lower?

[Linn@Amazon]

this is the latest ported Eaton cars we did ;keep in mind we have a Mustang Dyno and it is about 5% diff than a dyno Jet

this is an AR ported Eaton car<---this porting compares to the Stage 2 Steg port.our porter has been in Afghaistan and we never developed past the Stage 2 since he has been gone... he is back now tho

512hp/ 539tq


03 Cobra Redfire Vert (NEW RIDE)
2.8/4lb/AR port/AR cai/o/r x-pipe/dynomax cb/sct 2400 maf/metco 90mm idler
Amazon Racing Tuned with pride!!!



this is a Steg Ported car;

522 whp SAE
537 wtq SAE
STG IV Steig port
LFP heat exchanger
2.8 upper
4lb lower
bbk l/t's
bbk o/r x
slp loudmouth
Johny Lightning coldair
Seimens 60 lbers
sct 2400 maf
NGK tr6's
MM full length subframes
DFX Clutch and 26 spline input shaft
Billet flow irs brace
pro 5.0 shifter
Nitto 315's
KB boosta pump
Tuned by Rick @ Amazon Racing!

[Linn@Amazon]

there is a knats eyelash diff in the 275/280 pulley so you can use these for comparison..


as long as you have a good tune you can run a 4# lower with either the 280 or 275 safetly and with very nice results


I see that you are from N.O. we are getting a dyno tuning day together for that area if you are interested http://www.svtperformance.com/forums...d.php?t=257455