Outer Limits 4x4 Board

Hi i've been noticing a few pretty hot 4.2 petrol patrols on here but everywhere i try to order even a simple mild cam and 4 barrle carby adator just look at me like im a spastic and say they've never heard of it or cant get me anything. So i thought i would turn to the wealth of knowledge that is outers and ask you guys and girls where possibly i might be able to try and find some parts to get the old slug moving.

Any help greatly appreciated thanks ppl.
Cheers Gary...

a 4brl adaptor is wast of time anyway. the only carbs you could even get close to working are the holley 450 mechanical single pumper
or a 465vac sec

neither of which will you get to work very well.

far better of going with a 2brl, either 7448 350 holley or a barry grant road demon 350. can't recall the part number, but redline do an adapter that fits with slight modifying of the bolt holes.

pacemaker do extractors for the 4.2L the part number is PH 9500
any exhaust shop can build you a 2.5 inch system.

talk to surecam http://www.surecam.com.au/ about a camshaft, they do alot of custom grinding, if you tell them exactly what you need the engine to do they grind a cam to suit.

ditch the points ignition and fit a crane XR3000 optical pick-up conversion. and fit a and MSD blaster HVC coil. (it's epoxy filled so vibration won't hurt the windings)

if you want to go further rip the head off and have it ported

thanks chevlux. this may be a stupid question but why could i not get say a 650 to run if i jetted it back these motors are a 4.2 so is a 253 and i see plenty of 253's runnig 4 barrels?

Even though theyre the same capacity motor, theyre essentially completely different.

The TB42 is basically a truck motor. It doesnt rev, it has torque.

Stick with the advice given, ditch the thought of using a 4 barrel carby, and play with what is tried and proven.

* Electronic Ignition

* Extractors

* 2.5" to 3" exhaust

* When the headgasket goes, get the some headwork done

If you want more than that, search the many many threads on turbo conversions

MQCRAZY wrote:thanks chevlux. this may be a stupid question but why could i not get say a 650 to run if i jetted it back these motors are a 4.2 so is a 253 and i see plenty of 253's runnig 4 barrels?

most of those 253s are using the 450. yeah they can be made to work, but the problem is the 450 is a mechanical secondary carb but it only has an accelorator pump on the primary side. on smaller engines eg: less then 5L they tend to have a flat spot as the secondary side opens. 650 is quite simply twice the carburation that the engine needs.

it's not about jetting, it's about air flow and the signal that the air flow creates and the discharge nozzle. big carbs on small engines have a very weak signal. the smaller 350 will have a good stronge signal and will be responsive and crisp to drive, which is what makes for a good street engine.

http://www.holley.com/division/Holley.asp
got o the above link and at the top you see a box with ENTER YOUR CID put in 253 and follow the prompts.
do it for both the 2brl and the 4 brl, answer the questions honestly and check the result.
It will recomend the 350 for the 2brl and the 390 and 470 in the 4brl vacuum secondary.
the problem with the 4brl even the small ones, is your manifold is based on a 2brl carb, and the lack of 4brl adapters for the nissan manifold.

Hey Brad, Has anyone looked into multiple carbs. Like side drafts etc. There would be a bit of custom fab but it would look horn.

toughnut wrote:Hey Brad, Has anyone looked into multiple carbs. Like side drafts etc. There would be a bit of custom fab but it would look horn.

the problem with S/D webers is cost. at almost $1000 each for new ones.

i've got one word for you. put motor bike carbs on it.

i mean how many bikes have you seen standing on the back wheel almost vertical and still running perfectly fine. There would need to be abit of custom fab and tunning but 6 40mm constant velocity carbs would go quite well.
www.boggbros.co.uk these guys will put bike carbs on almost anything

but thats prolly a bit over the top.

That would look awesome with a custom plenem chamber and snorkle.

I was lookin at bike carbs on my tb POS but sold it. There are a wide variety of carbs around with different applications, 39mm kihan smooth bores would be good but $, or 40mm kihan CV carbs from zzr1100 are proberly cheap enough now.

The ZZR's run air ram feed so would be good with a snorkel.

I dont think DCOE webers would be any good on side angles as the fuel would run from the bowl into the jets, but it would run great on the flat. Having said that it would be interesting to try it cos LYNX did a manifold to suit DCOE to Z900 Kwaka's. Most people I know said the webers on the Zeds was realy only good for dragracing though.

Any one tried a mighty deamon Blow through carb? I was also thinkin bout one of these with turbo on the tb but wasnt sure bout the angles, they are around the $1000 mark also though.