Gav240z

What everyone else said except a couple of things to add. Firstly you said you have a 73 right? in the states they are flat tops at this stage correct? If so then you want an earlier set 69-72 carbs. www.ztherapy.com hope that link works good explanation. Tripples are even better and webbers seem to have the biggest bragging right. However they work best on a larger camshaft profile and porting, valve work etc.. THey are not worth while without the internal engine work. You can get a Z going 12.8 down the 1/4 with SU's but they will require some work. Boaring out the throats larger needles and seats and you will probably wanna do some porting to the intake manifold also. My opinion don't even consider anything that isn't sidedraft on a straight 6.:classic: PS: 1 other thing F.I is the best especially a multiple throttle body set up. The ZX injection system will probably loose you power over the SU's. But it will be a better DD.

back to the drawing board for me. 4 / 10 I need to practice some more I think. :classic:

You make it sound like a video game. If it was done just tops it all off. IF I had a 24 cylinder mustang airplane engine in my Z that was supercharged it would do the same thing. If it was done . Seriously I don't know what your getting at but you'll find at this site we don't tolerate comments like this!

ummm how old are you?

To be honest I thought of exactly the same thing , I am not saying your full of crap or anything I believe it I just thought it was funny also .

I am glad to hear you are happy and I wouldn't personally worry about it effecting the cars originality what fun is a auto sports car in the first place? The 3.54 gear ratio is ok I'm looking at putting in a 4:11 into my Z at some stage I really want her to boogie . I recently installed a lighter flywheel and enjoy the way it revs but I feel that the revs drop quicker with the lighter wheel than with the heavier one. My new clutch made a huge difference also it really grips and makes changing gears a real thrill as it lurches the whole car forward straight away. Glad to hear your enjoying it . I am

I have no idea what your uncles car is but are you sure there's no way you could beat him in the corners the Z can be quite a weapon once set up right. Gav,

Put me down for BRE everything else is too ricey.

yeah I'm playing with the idea of switching engine heads or building another engine. Still unsure . Good to see you've made some progress there I know what fun it is removing it just havn't discovered how much fun it is to put it back.

What Steve(zvoiture) is saying, is in a nutshell yes you can do it but to be completely honest they look messy and they really don't do anything. If your using a stock intake and carbs say SU's. Then the airbox points so close to the front of the engine bay that it's practically perfect how it is. If you have a 280zx or 280z with FI which i don't think you do with a L26 in there then you can use what other steven has shown. There are other pods you can put on the front of the SU's but honestly they just soak up the heat from the exhaust manifold. :classic:

James just saw the post after I wrote you a PM. I know I have 1 set of flat tops in my n42 motor in the other 2 F54's I am not sure so as I said in the PM will let you know however it may not be for a while. Gav,

Alan do they choose the N42 for big bore's due to the F54 having the webbing around each cylinder? I am just wondering I have 2 F54's and a N42 at my house and don't wanna throw them out but space restrictions may mean i have to. However I was gonna go a max of 30 thou overbore so it might not be so bad. The 280c may have a F54 because it was fitted later in it's life it's hard to know in these old cars. Their history anyway. I am with Alan about the engine though if you don't wanna just put it straight in and will be doing some internal work it should be fine. It is an L6 after all.

Why don't you just run it down the 1/4 mile.

are you kidding about this you must be? It looks like junk if you ask me? Where does it sit? I can't picture this anywhere on a Z. You are joking arn't you? I think you are and i've just fallen for it. Sorry if you actually did like it. :sick:

Thanks for the links my friends, I have read a couple of those previously the more I read them the less there is to it. It's just sourcing the parts really. I have the flat tops the F54(2 actually) P90, I can get the l24 rods or even l20b rods pretty easily. The SU's are used on the set up currenly(Which I love) , but it won't supply fuel till 8400rpm gotta really use the webbers for that it currently goes flat around 7000rpm. So he's tinkering with the idea of putting those on or even tripple SU's like the old jags. I will definately try take pics of his car next time i see it, it's really a beautiful Z.

To my knowledge so far it's like this. P90 Head F54 Block L20B(4Cylinder) Rods. LD28 Crank. 260z Gearbox 4:11 Diff. SU's Ok for the work involved. The P90 head will be pretty wildly ported. Flat Top Pistons installed. 30 thou overbore. ~ 3.1 litre with LD28 Crank. Remapped Distributor(Revs out to 8400rpm). The SU's have their throats ported and the intake manifold is heavily ported. Not sure on Camshaft Profile. Valves still not certain. Comp ratio probably 10:1 Not sure on treatment of bottom end of motor in the way of shot peening, balancing etc.. As I said I'm getting a rough idea of the specs of the motor I know he's willing to help me out with it just gotta save the money. The car should pull low 13's possibly high 12's with this set up. in a 240z anyway 260z with some weight loss probably the same. I'm not engine building expert however hopefully I will learn alot about it soon.

hmmm usually backfire through the intake is a result of a lean condition. I am not an EFI expert so this is kinda a hard one for me. Is it possible that both AFM's are faulty? How did the other car run? By changing the AFM you could have changed a few things that were set up with the tune of your old AFM. Could even be electrical timing. although I'm not saying it is. Good luck. Gav,