[DiZzyBonne]

I was wondering, and what power goal is it worth the switch? To make things easier, lets say I had the choice of buying a SOHC Mustang and a DOHC Mustang (not a Termie, but lets just assume they made one, so it's not forged.) Obviously the DOHC would cost more. If I was aiming for 400 RWHP, the 2 valve would be the better bang-for-buck choice. At which power goal would the DOHC be worth it? Also, which is more expensive to mod? Lastly, up to which HP would which one be cheaper? By that I mean, lets say I spent $10,000 on the SOHC Mustang and $12,000 on the DOHC Mustang. Which would be cheaper to get to 400 RWHP, 500 RWHP, etc. So to sum it all up;

1) At which power goal would the DOHC start to shine?
2) Which would be cheaper to get to 400 RWHP? 500 RWHP? 600 RWHP?

Thanks!

[v606er]

im not sure. reverend seems to know a lot about this sortta thing though

[G.T. Rags]

my head hurts from reading all that.

it's cheaper to mod a 2v then it is a 4v
you can make more power easier with a 4v then u can with a 2v.
u won't make 500rwhp on motor with any of these motors, u need FI, and a built block.

[DiZzyBonne]

First you say it's cheaper to mod a 2 valve, but then you kind of contradict yourself saying it's easier to mod a 4 valve? Also, I know you need F/I, but at which point would the 4 valve be worth it?

[ReverendDexter]

Originally Posted by v606er im not sure. reverend seems to know a lot about this sortta thing though

Heh, I appreciate it. Honestly, this one's a little out of my league though. I can really only speculate, but here goes:

It's not going to matter.

The 4v is going to respond better to modifications. BUT the available mods are fewer, and more expensive. Yes, the heads flow better. A lot better. But under boost, that's not going to matter as much as your bottom end will. In which case the early 4v block is better, but you're going to have to replace the internals anyway.

The difference really shines under light mods, not heavy mods. Heavy mods can turn the most dogly of motors into a beast.

I know that doesn't answer your question, but I'm not sure that there really is one.

[DiZzyBonne]

Well if you were to get a blower, would there be a huge difference at like 9 PSI? What about more? Thanks for all your help .

[G.T. Rags]

Originally Posted by DiZzyBonne First you say it's cheaper to mod a 2 valve, but then you kind of contradict yourself saying it's easier to mod a 4 valve? Also, I know you need F/I, but at which point would the 4 valve be worth it?

the Rev pretty much clarifies it

Originally Posted by ReverendDexter Heh, I appreciate it. Honestly, this one's a little out of my league though. I can really only speculate, but here goes: It's not going to matter. The 4v is going to respond better to modifications. BUT the available mods are fewer, and more expensive. Yes, the heads flow better. A lot better. But under boost, that's not going to matter as much as your bottom end will. In which case the early 4v block is better, but you're going to have to replace the internals anyway. The difference really shines under light mods, not heavy mods. Heavy mods can turn the most dogly of motors into a beast. I know that doesn't answer your question, but I'm not sure that there really is one.

[DiZzyBonne]

Yeah he did. It's easier to make power with light bolt-ons with a 4 valve, but it's gonna cost you more.

[G.T. Rags]

exactly.......

When u buy a Cobra, ur buying an all around better machine. But you pay for it.

[DiZzyBonne]

I'm just curious to see if the 4 valve really justifies itself in cost if you're only aiming for like 400 RWHP, that's my main goal lol.

[G.T. Rags]

Originally Posted by DiZzyBonne I'm just curious to see if the 4 valve really justifies itself in cost if you're only aiming for like 400 RWHP, that's my main goal lol.

honestly?

it's gonna cost about the same to get either car up that high. Only dif is u can do it with just bolt on's with the 4v and u need a FI with the 2v.

[DiZzyBonne]

A 400 RWHP bolt-on 4 valve, didn't know it was possible.

[G.T. Rags]

Originally Posted by DiZzyBonne A 400 RWHP bolt-on 4 valve, didn't know it was possible.

when i say bolt on, i mean FULL Exhaust, Pulleys, Intake, Cams, tune, new ignition system

[DiZzyBonne]

Oh okay, makes sense.

[iraziel]

Originally Posted by ReverendDexter But under boost, that's not going to matter as much ...

I can vouch for that. I was running a stock 02 GT w/ P1SC 8lbs boost (and Magnaflow mufflers). I would run with a termi until half through third gear, then his top end would take it.

Modding a 2v is deff cheaper.

[Eagle2000GT]

They do make 4v non-forged motors. Mach 1s and 99, 01 Cobras. First, 4v motors breathe better than 2v motors; therefore, bolt-on give you a better horsepower gain. Second, I have heard of high 3xx rwhp with a n/a 4v. Third, neither motor will make 400 rwhp without FI. Fourth, the rods are still the limiting factor unless you have a terminator.

Stock 4v > Stock 2v
FI 2v > Stock 4v
FI 2v = FI 4v
FI forged 2v > FI 4v
FI Forged 4v > FI Forged 2v

The least expensive way to 400 rwhp is a GT with FI. If you intend to go further than that buy a terminator.

[ReverendDexter]

I'd also like to ad that a 400 hp N/A 4v is most likely NOT going to be streetable due to the cams you'd have to be running. If my goal was 400rwhp with my car, I'd do it with a few bolt-ons and a 100-shot of nitrous. If it was 450 or more, I'd get boosty.

If someone has a counterexample to this, I'd love to see it.

Another thing I was thinking about was the upper limits. I believe that it's possible to build a 1,000hp 4v without having to port the heads (B-port heads, at least). I don't think you can say the same with a 2v. With the b-port engine, you could also keep your stock block at that power level.

And that's not even bringing a Terminator motor into play.

My personal opinion is that if you're going to do heavy mods, your best bet is to start with either a Terminator or a B-port motor. Those will give you the strongest blocks and the best flowing heads to work with. If you're shooting for bolt-ons or light boost, work with what you have already.

Sorry if that's reiterating what's already said.

[DiZzyBonne]

My goal for now is 400 RWHP. If I ever decide for more, I'll probably either put more into my current motor until it blows to give me a reason to get a built MMR shortblock OR just buy an MMR shortblock from the start, which will then bump up my new goal to who knows how much! 666 HP or RWHP sounds nice .

[banned]

I love all these buy a termie posts... such a waste, crap blower, alot of crap parts, decent internals - but weaker than aftermarket - oh and its alot more expensive base car to start with. The 4v is best flowing head, 3v almost match them and are alot more simple - simple = reliable. 2v is the most reliable mod motor by far, all can make what ever power you want, better flowing heads just make it easier, cost between them all is really not much different - your talkin a 1500-2500 dollar difference, nothing in the long run. That said, I went with a 5.4 4v for my project, but it all depends on your goals, a 2v can make for a faster street car then you would want to ride in, so dont get too caught up in the 15 yr old cobra worship... most of it is straight BS. Suspension is big, a 450 rwhp with a good suspension with toast a run of the KB termie with 550-650 rwhp (which most are liars and dont make that kind of power anyway, just my .02)

SO to answer your question, with forged internals and stage 3 heads (2v) and FI you be as fast as you want to go, the truth is that 4v heads and ported 2v heads are about the same cost give or take, the 4v is better, the 2v is easier and cheaper and more reliable.

Long story short, get a turbo... and if you need more run some juice - 2v vs. 4v is over rated, but dont be mistaken it is important, you need to pick a tranny, gear, power adder etc, that keeps you in your powerband for as long as possible and suspension that can take it.

[HBK_2007]

i decided along time ago that it would be cheaper for me to get what i wanted out of a 2v than a 4v