freshinXR

hey whats up. i got a 66 xr falcon coming back from the panel shop soon with fresh paint. its got a 250 pre cross flow in it. when it comes back i was looking at spending about a $1000 more on it. would it be worth spending it on the 250 pre crossflow or put a 250 x flow in it. if you think one is better than the other what mods should i be looking at to get a good gain. I know a 2v head and exaust system are the go for the pre cross flow but what else? would those gains be the equivalent to the mods done to a 250 x flow. i hope someone understands me, i'm starting to confuse myself now.

xf351gt

allways a fan of the crossflow the stock heads flow far better than any 2v precross flow head.

i had a 170 in the xp built a worked alloy head 250 crossflow the reasons where that could not find many parts no performance parts at all.

you should be able to find a fresh engine or get a complete one a rebore for the price.

the conversion if you deside to complete this mission should go ahead easy.
this message might self destruct in ten seconds.

tic tic tic tic.

73gscoupe

Why a six? why not a 289 or 302 windsor? they're a good motor, will look at home in the engine bay, and has plenty of parts available.

The 250 pre x flows are not a particulary good motor performance wise. only bother if you can find a 2 V head (seperate inlet manifold). I dont mind them because they're something different, but if performace was your goal you would not start with one.

The x flow motors are better performance wise, and are pretty cheap. many aftermarket parts available, but the standard 2 barrel motors are a good bit of gear. would have more potential than pre x flow motor.

freshinXR

yeah i was waiting for someone to ask about an 8. basically i'm only a student and can't afford to pay the cash needed to put an 8 in (disk brakes, box,diff ect..) especially after the 5 grand paint job, not unless there is a nice person out there who wants to do it all for free. thought not. So i guess i'll keep my plans at doing up a 6. Really i only want a bit of performance and a nice tone. my opinion on building something quick is why bother when there is always something out there quicker. usable power is something i'm aiming for.

outback_ute

You're right the V8 will blow the budget out of the water. PS, do you have front discs now? Prob solid discs I suppose, otherwise if 4-wheel drums then perhaps a front disc conversion might be the way to go instead.

Definitely go the cross-flow, as you say there are actually bits available for them, and its a much better base to start from.

freshinXR

ok so it looks like the cross flow is the winner, but what type. efi or straight carby? i thougth the efi would be better but then i thought about the ability to wack a holley or something like that in place.

tiggers_ef

well i actually built a pre x-flow motor from scratch and still have it i actually had the intake cut and a lynx manifold bolted on with 308 stainless valves intake ported, exhaust ported and polished by a place in morrabbin melbourne that expected nothing less than 260bhp.i fitted 45 dcoe side draft webbers bolted to the bottom half which was acctually balanced and machined by the head mechanic that built peter brocks xu1 torana motors.hehehe only problem was it streched double row roller cam chains

also had a mate that had a xr with 302 windsor with twin side draft webbers all thats was needed was cam good running gear good box and 11" clutch plate put you in back seat

xf351gt

i think carby your going to blow the budget with the efi i had the efi in the xp before ended up riping the efi of to unrelable after swaping tps airflow dizzy etc list go`s on theres plenty of parts out there but diagnosing the problem mine bad a problem that had the experts stumped.

also extra time with the efi would be adding a return line and the expence of a external fuel pump $200+ plus can only go so far performance wise with cam upgrades with out replacing computers.

this photo is when mine xp was a efi

http://www.fordgallery.com/showphoto...cat/500/page/1

freshinXR

hey tiggers_ef sounds like you got a nice engine there. is it in a car or what. feel like selling it. how much did it cost you to get that sorta setup going.

Pneumatic

X flow with a holley 350 all the way

i have a 200cui cortina crossflow (3.3L six), just got some extractors, redline manifold and holley 350 carbie for $220. total cost after new exhaust and carbie fitted, tuned, new accelerator cable etc, is about $700. money very well spent.

So much torque/response at bottom end you'd think its a manual, no lag or flat spots, cains our EL automatic for accelerator response. first time i drove it after the carbie was installed, i spun the wheels on a speed bump (used to the old laggy engine) in a shopping centre and almost hit a grandma. can u picture any old 1970's sluggish falcon doin that? idles a lil rough, with the new exhaust sounds like a v8. spun out in the wet while playin around, no damage, just didnt expect to have so much response from her, in 2nd gear too :D

carburettor has size 61 jets and massive venturis (like that wen i bought it). people say holleys are only good for a drink o fuel, done me a world of wonder. fuel consumption is marginally more because i used to push the gas pedal down a fair bit to get over the accelerator flat spot on the old carbie (accelerator pump on standard stromberg carbie was stuffed).

webbers are ok..... fiddly too.... holley are more common (in my area anyway), simpler and self serviceable wen you know a little about what you're doing.

must do the extractors if you do the carbie, if you can get twice the air in, need to get it out too.