i wanted to ask you guys what you think about it? i am currently running stg 2 sean hyland cams. The car lost power as opposed to gaining power in any power range. I was told the (stock)intake mani i have does not flow enough to handle the cams, and the 99+ intake/head swap would help.

-what are some pro's and con's?
-does there require any wiring modifications?
-can you direct me to any threads/posts or write-ups on the swap

thanks in advance
jack

 

I dont think you will see any overall HP gains to justify the cost of doing the swap. The power levels between the 2 heads and intakes will be similar. The early B heads (96 - 98 Cobra) actually flow better then the later C heads. Under boost you would do better with B heads. They make most of their power at upper end of the RPM band. The later 4v heads make better low end hp and torque compared to B heads. They work well with boost also,.. but for all out RPM hp,.. the B heads are a better choice in my opinion. On the street you would probably do better with the later heads because of the broader torque curve. But if you compare dyno graphs the later heads fall off earlier then the B heads do.

Get with Bitmark or BVH on this as both of those guys have a lot of experience on these motors. I know my way around them,.. but I am by no means an expert on them.

Have you tried extrude honing or porting your intake? Someone correct me if I'm wrong,.. but I doubt cams on a 4v will cause even a stock intake to become a flow restriction. 96 - 98 4v motors are very limited on cam choice because of PTV clearence issues. Have you had it tuned with the new cams? Did you degree the cams in? If not,.. theres a good bit of power lost right there. Are you still running IMRC plates? What kind of TB and air intake are you using? Are you NA or running a power adder?

The 96 - 98 motors are pretty good. A small shot of spray can bring them right up to the ragged edge of reliability. They have a forged crank,. but still share the weak rods and piston that the GT's used. Anything above 425 - 450hp is borrowed time and on a small blower or NOS they can easily reach that number.

If you decide to do the swap,.. its pretty straight forward. You dont have to switch to COP ignition,.. you can still use your coil packs and stock wiring.

Hurst

 

how much power did you lose and do you have dyno charts to verify ? a over layed graph would be able to point you in in the direction. but b heads are great heads and the intake can use a little work but is a good intake . get the dyno graphs and lets take a look.

 

i only got a street tune thus far, yet i am on a limited budget, but i may be able to afford some new pistons and rods here soon.
i was told the b heads flow better, but only slightly. From what i hear no one makes an aftermarket intake manifold for my 96 that is decently priced.
i have a nitrous kit waiting for it, but i wanted to have the motor running good before hand. I am just so lost with these 4.6 motors it's not even funny. I have to rely on the info i get from others to even think about what i have to do next.

to answer hurst:
i have an accufab TB / c&l intake tube/ mac inside the fender cai
im n/a for now. i also still have the IMRC's.
not sure if cams were degreed or not.
i had Genium performance put the cams in about a yr or more ago.

im just very lost with the car right now and hate the loss of power...

 

Stage 2 cams per SHM site says they are a .474 intake .452 exhaust and 235/225 duration. The large of a cam requires a stronger spring. You running stock springs? Were the cams degreed or just replaced back to original settings? If installed incorrect you could have retarded the cam timing worse that what it was and have a loss of power. However those cams will most likely raise your peak rpm power (if installed correctly) and the intake probably isn't moving enough air for those cams but you still should have made more power in any range over stock cams.

99+ intakes won't work with your b-heads. What you need is a shortrunner b-headed intake. That will compliment those cams. But I'd pull a valve cover first to see if you have a broken spring. Then if not do a compression test. If the numbers are low it could be the cam timing.

Hope this helps. Oh btw, I happen to make custom shortrunners for the b-heads.

-Mark

 

if you have the parts for the 99 4v set up pm me what you have. I have the b-type heads , irmcs,and cut short runner intake for the 96-98 cobras. We can work out a trade

But the parts from a 99-04 will not work ok your car without modification

 

i replaced the stock springs with an aftermarket set. don't know which ones though. i"m not sure about how the cams were installed but i know im not making as much power in any range as i was before the cam swap.

bitemark...... do you mind if i can meet up with you sometime and maybe you can take a look at my car? i"m not real sure on what's goin on n e more to be honest. i'm stumped....

 

you have no headers? and your intake is stock ? if you up grade the cams but your motor dosent move air effectively that would calse most of your problems . there is a list of stuff you should of done befor cams imo . i think your best move would be let bitemark rework your intake.

 

sorry i have long tubes X pipe into a mac catback... i forgot to mention that.
although i dont think it would be in need of more fuel i kept the stock fuel injectors with an aeromotive fpr.

i want to thank you guys in advance for the info you guys are giving me

 

Cams are a very expensive upgrade. I assumed he had exhausted all of the bolt on's before moving on to do cams. Thats typically what most people do. Especially when considering the cost involved. Many dont bother with cams on a 4V motor,.. particularly the 96 - 98. I have heard of 99 - 04 guys taking the exhaust cam from the 96 - 98 motors and using them with good results.

This is a case of installing a mod with out the supporting mods that are required in order to see the most. I'm willing to bet LT's and mid pipe really wake this motor up. Have to keep in mind these early 4v motors dont have a lot of low end torque. My 2v GT had more low end torque then our 96 Cobra did. But after 4000 RPM the comparison ended and the Cobra clearly pulled out ahead. These motors love to rev.


Hurst