4.6 for Boost

[tjm73]

I am considering building a stout 4.6 for a Kenne Bell setup for my '98 GT.

I did a spreadsheet with as many of the parts as I could think of and added it up. Now this is JUST parts. All told I came up with just over $5500. To that, I would have to add the KB kit, install and tune. At least another $6500.

The engine would have....
New FRPP block
ARP head studs
All Fel-Pro gaskets
FRPP SFI Damper
Moroso 7qrt oil pan
FRPP high volume oil pump
Cobra steel crank
Probe dished pistons
Scat h-beam rods
New main & rod bearings
Stage III ported PI heads
Cams
All new timing set
FRPP stainless headers

The PI heads with the dished pistons would give a 9:1 compression ratio.


Now the thing that strikes me is I'd have at least $12,000 wrapped up in an engine (no tranny, suspension, etc...) for a 1998 GT. It'd make a ton of power but it'd just be a '98 GT. Nothing particularly special. 1998 was one of the highest production years ever.

Seems it would be smarter to take that "$12,000" and put it down on a 2003 or 2004 Cobra. Would have a lot more car and it's a collectable car, which means it's always going to be more valuable.

What do you guys think?

 

[back_in_black]

I had an 03 cobra and if you crank up the boost on your cobra, like most people do, you will probabaly be rebuilding the lower end of that engine as well. Many cobra guys switch from the heaton blower to a KB or whipple, probably still put new wheels and tires. If you like to drag race, you might even switch from the irs to solid rear or even switch out to an auto ! I guess if you were going to buy an 03-04 cobra and not mod it what so ever it would be a better investment, but who doesn't mod ?
Besides that, there is that nasty head tick that my cobra got, "SVT knows about the problem , but does not have a fix!" I had my driver's side head switched twice and the ticking noise, (sounded more like a rod knock) got louder. If you wait until the new cobra comes out you will be able to pick up an 03-04 a lot cheaper because a lot of those guys are sick of the problems they have been having, and the new setup has a lot more potential ! Bottom line is, yes you will be starting out with more performance, but modding is what it is all about, I see lots of 03-04 cobras, but I don't see as many 500 rwhp gt's.......and if you are going to mod your 03-04 cobra you are making it worth less !

 

[tjm73]

I had an 03 cobra and if you crank up the boost on your cobra, like most people do, you will probabaly be rebuilding the lower end of that engine as well. Many cobra guys switch from the heaton blower to a KB or whipple, probably still put new wheels and tires. If you like to drag race, you might even switch from the irs to solid rear or even switch out to an auto ! I guess if you were going to buy an 03-04 cobra and not mod it what so ever it would be a better investment, but who doesn't mod ?
Besides that, there is that nasty head tick that my cobra got, "SVT knows about the problem , but does not have a fix!" I had my driver's side head switched twice and the ticking noise, (sounded more like a rod knock) got louder. If you wait until the new cobra comes out you will be able to pick up an 03-04 a lot cheaper because a lot of those guys are sick of the problems they have been having, and the new setup has a lot more potential ! Bottom line is, yes you will be starting out with more performance, but modding is what it is all about, I see lots of 03-04 cobras, but I don't see as many 500 rwhp gt's.......and if you are going to mod your 03-04 cobra you are making it worth less !

I've never hear dof this problem you speak of.....interesting.

I love my '98 GT. It's a coupe. Black with black leather inside. Super clean. 100% stock except for Magna Flow cat-back and UPR shifter. Just needs lots more power.

If I got a Cobra I'd do the FRPP/Whipple upgrade, upgrade the exhaust and like you said put some different wheels on it. Then just drive it. It would got to the track once and a while, but not often.

 

[edbo]

Dude, if you're going to spend that much on a stout engine, forget the KB setup and build one with Twin Turbos and become a Cobra killer! Looks like you would have a killer setup with that list of parts though.

 

[300bhp/ton]

I know this is a Mustang site and I'd probably get flamed for this, but if you are looking at spending some money ever considered an earlier Dodge Viper GTS, they must be similar money to a 03 Cobra but be even more exclusive and have enough bhp to begin with even totally stock.

 

[edbo]

Just thought this link might be interesting to you! Check it out, it rocks!

 

[tjm73]

I know this is a Mustang site and I'd probably get flamed for this, but if you are looking at spending some money ever considered an earlier Dodge Viper GTS, they must be similar money to a 03 Cobra but be even more exclusive and have enough bhp to begin with even totally stock.

I wouldn't flame you for it. But I'll never own a Chrylser product.

 

[Superhereaux]

I wouldn't flame you for it. But I'll never own a Chrylser product.

a viper really isn't a chrysler product. its like saying i'll never buy a lamborghini because its a vw (lambo's owned by vw group). the only thing chrysler about it is the dodge name. everything else is pretty much one off viper exclusive

as for your '98, if you want to build a stout block, all you'd really need is the internals and heads. the new block you don't need. dampner, oil pan and oil pump you don't need. you don't need new cams or ported heads either. new timing set? unless this is a full on, balls deep, 8k rpm endurance style race engine you really don't need all of this

stock pi heads/cams and forged guts is all you really need to run the kb to well over 500rwhp. you also need to consider the cost of the upgraded fuel/ignition system if it doesn't already come with the kb kit. all that work but i'd still keep it instead of buying a cobra

 

[tjm73]

as for your '98, if you want to build a stout block, all you'd really need is the internals and heads. the new block you don't need. dampner, oil pan and oil pump you don't need. you don't need new cams or ported heads either. new timing set? unless this is a full on, balls deep, 8k rpm endurance style race engine you really don't need all of this

stock pi heads/cams and forged guts is all you really need to run the kb to well over 500rwhp. you also need to consider the cost of the upgraded fuel/ignition system if it doesn't already come with the kb kit. all that work but i'd still keep it instead of buying a cobra

Good points. I'll recalculate out of curiosity.

BTW who is that in your avatar?

 

[tjm73]

Dropping...the

FRPP SFI Damper
Moroso 7qrt oil pan
FRPP high volume oil pump
Stage III ported PI heads
Cams
All new timing set

and adding the 'out of the box' PI heads while retaining the new block (to minimize down time plus it cheaper than machining the block that's in the car) and keeping the head studs to maximize sealing it drops to about $3300.

That's much better.

Really, my goal would be 400-450 rwhp in a totally reliable package. I tend to "over-engineer" things.

 

[edbo]

Good luck with the build up. I hope to be doing my '98 early next year. I would like to get an aluminum block and do my build up with but may just purchase a used PI Motor and do some mods before dropping it in.

 

[white99gt]

Dropping...the

FRPP SFI Damper
Moroso 7qrt oil pan
FRPP high volume oil pump
Stage III ported PI heads
Cams
All new timing set

and adding the 'out of the box' PI heads while retaining the new block (to minimize down time plus it cheaper than machining the block that's in the car) and keeping the head studs to maximize sealing it drops to about $3300.

That's much better.

Really, my goal would be 400-450 rwhp in a totally reliable package. I tend to "over-engineer" things.

Well to add to your original list .I would drop the scat rods,and probe pistons.I would go with diamond or cp pistons and manley rods with arp 2000 rod bolts.

Keep the moroso oil pan ,mod motors need their oil (research spun bearings you will see).

The oil pump is a given but a good high volume pump with a set of billet gears is pretty much bullitt proof.

I would build the shortblock as stout as possible.There are plenty of gains in heads and cams to.

example.
9.5:1 compression(stock) cp pistons(17cc)
eagle rods
cobra crank
ported heads
custom comp cams
bullitt intake(stock)
longtubes
vortech s trim (10 psi) no power pipe 3.33 pulley

463rwhp on a MILD pump gas tune..(my first blower setup on my car).
Same setup with a little more boost made 555rwhp on a safe pump gas tune..And then made 621rwhp..


Moral is build it once.Then you can turn up the boost as you want it..

 

[wms004]

I know this is a Mustang site and I'd probably get flamed for this, but if you are looking at spending some money ever considered an earlier Dodge Viper GTS, they must be similar money to a 03 Cobra but be even more exclusive and have enough bhp to begin with even totally stock.

Its cheaper to make the mustang faster. The 03 cobra is 30 grand, but its built to take a lot more boost because of the internals and compression ratio. A supercharger on a viper is only safe up to about 6-8 PSI to my knowledge, and thats what the cobra comes with stock (8). With about 1k in mods (tune, pulley, exhaust), you can put the cobra around 470hp at the wheels.