Souping Up A 250 2v

[Lumpen]

Ive got a mate who mucks around a bit with the 250 crossflow but not the earlier 2v. Im not sure how boat motors differ from car motors spec wise, but id expect an improvement if you used triple webbers or aftermarket injection. I guess it depends on actually whats inside the motor now and how much you want to spend?

Shane

The 250 2V is actually getting pretty thin on the ground now. From memory they were only run in the XY and XA models? It might even be a better proposition to chuck in an Alloy Head Crossflow (same mounts) and keep the 2v for prosperity or til they are 'collectable'.

Other than that, I had a mate who had a 17 or so foot ski boat with a genuine E49 spec R/T Charger engine with tripple webbers and all that carry on, could pull a skier at just on 60MPh! If you want to keep the 2v I would suggest look at what they were doing with the R/T's and XU-1's in that period. Rorty cam's, high flow exhaust, big valves and lotsa carbies.

Lumpy

[Guest chubbs]

As for whats inside the motor now, and how much I want to spend: I'm just assuming the motor is rebuilt stock, and don't want to spend any more than a grand. I've just heard figures like 200hp being possible, and I'm curious to see what's involved.

[Lumpen]

As for whats inside the motor now, and how much I want to spend: I'm just assuming the motor is rebuilt stock, and don't want to spend any more than a grand. I've just heard figures like 200hp being possible, and I'm curious to see what's involved.

These motors can have a fair bit of torque when you work on them a bit. For a grand you might do best to clean the head up a bit and shave a bit off it too just to knock your compression up rather than rebuild with high comp pistons and such.

Also a bigger cam and maybe roller rockers will go a long way to opening a 250 up, just don't know how much this would add to the price.

Lumpy

[xr6t ute]

As for whats inside the motor now, and how much I want to spend: I'm just assuming the motor is rebuilt stock, and don't want to spend any more than a grand. I've just heard figures like 200hp being possible, and I'm curious to see what's involved.

<{POST_SNAPBACK}>

A grand isnt a hell of a lot to play with, but if your handy with the spanners and can do a bit yourself (like remove and refit the head), you could get some port work done on the head if its in good condition and nothing else needs to be done. A cam change will help to but depending on what can be reused will govern the final cost.

Shane

[blueboost]

get the head reconed to suit unleaded, (if not allready done ) shave head, to lift compression to about 10 to1. put small cam in, (one that makes good power to 5000rpm) 63 main jets in 350 holly, or if you get hold of a 500 2 barrel holly, run 74 jets in that, and run it on pulp fuel, when you are flogging it, but you will be able to ski with norm unleaded to, with that compression. then prop too suit the 5000 rpm mark. with that power improvement you might not have to change props, because if close to standed now it will only go to about 4500rpm. but if not you can get your prop adjusted to suit your rpm for about $80.00 or so.hope this helps

David

[ZAP]

chubbs,

Gearboxes DO exist in boats. Some boats have reverse and netural as well as forward.

If the motor is not broken, keep it as is untill you need to replace it.

[sixfan]

WOHO!

yeah I've worked a 250 2v, spent a LOT of time getting it right.

Forget everything you know about high power engines, this beastie is different!

My advice, these motors DO NOT REV HIGH. Blue printing, balancing everything etc and I still kept mine down under 5000rpm. Having said that, It made HEAPS of power and the motor is as F'n solid as they come. Carefull with the head though, as they are prone to cracking, but if you don't overheat it it'll go forever. Often the first cause of lost performance on the 4.1's (pre xflow) was that the cam lobes wear down (that's after zillions of K's) another issue with these motors is that they run 9:1 compression and DO NOT LIKE the cr@p they sell as LRP. just use premium + an additive.

The whole high rev thing has to do with harmonics generated at high revs due to the pushrod length, if you want to "Fix" that, I'll buy the motor and you can put in something else....

Righto, how do you make heaps of power with an engine that does not like revving? This is what I did, and it worked wonders!

1: C.V Carbies... Use 3x1 3/4inch SU carbs (or even 3x2"), sorry, chuck out the holley. (we hates them!! ) the SU's will maintain low down torque and give better top end due to better fuel distribution. Your current setup will see the inner two cyls rich, the middle two about right and the outer two lean. SU's are the best carbies I have ever used.

2: If it won't rev, why the high lift cam? Don't. Put in a high torque cam. Trust me on this! it will make one hell of a difference and should not rob your top end.

3: extractors: forget headers, get a good set of interference extractors, again, this will help make torque.

4: Don't put in roller rockers or waste your cash on other high rev items (forged pistons, gear drives etc etc...). Use a high Vol Oil pump and replace the lifters with some High quality items.

this will get you making HEAPS of torque from 1500 to 4500 rpm.

the engines also respond well to turbo's and injection, but I never did that, so I can't comment!

P.S you have a VERY rare head there, from memory ~500 made it to Australia, I paid $500 for one in 1987.

Oh yeah, chuck out the Glass bowl fuel pump and replace it with a "Carter" (can be found in the wreckers, bolts up the sam.)

[sixfan]

and for the love of God DO NOT SHAVE THE HEAD!

This will only make it hard to start + prone to oveheating!

Been there, done that.

[stang]

WOHO!

yeah I've worked a 250 2v, spent a LOT of time getting it right.

Forget everything you know about high power engines, this beastie is different!

My advice, these motors DO NOT REV HIGH. Blue printing, balancing everything etc and I still kept mine down under 5000rpm. Having said that, It made HEAPS of power and the motor is as F'n solid as they come.  Carefull with the head though, as they are prone to cracking, but if you don't overheat it it'll go forever. Often the first cause of lost performance on the 4.1's (pre xflow) was that the cam lobes wear down (that's after zillions of K's) another issue with these motors is that they run 9:1 compression and DO NOT LIKE the cr@p they sell as LRP. just use premium + an additive.

The whole high rev thing has to do with harmonics generated at high revs due to the pushrod length, if you want to "Fix" that, I'll buy the motor and you can put in something else....

Righto, how do you make heaps of power with an engine that does not like revving? This is what I did, and it worked wonders!

1: C.V Carbies... Use 3x1 3/4inch SU carbs (or even 3x2"), sorry, chuck out the holley. (we hates them!! ) the SU's will maintain low down torque and give better top end due to better fuel distribution. Your current setup will see the inner two cyls rich, the middle two about right and the outer two lean. SU's are the best carbies I have ever used.

2: If it won't rev, why the high lift cam? Don't. Put in a high torque cam. Trust me on this! it will make one hell of a difference and should not rob your top end.

3: extractors: forget headers, get a good set of interference extractors, again, this will help make torque.

4: Don't put in roller rockers or waste your cash on other high rev items (forged pistons, gear drives etc etc...). Use a high Vol Oil pump and replace the lifters with some High quality items.

this will get you making HEAPS of torque from 1500 to 4500 rpm.

the engines also respond well to turbo's and injection, but I never did that, so I can't comment!

P.S you have a VERY rare head there, from memory ~500 made it to Australia, I paid $500 for one in 1987.

Oh yeah, chuck out the Glass bowl fuel pump and replace it with a "Carter" (can be found in the wreckers, bolts up the sam.)

I was wondering when someone was going to mention triple su`s.

The 250 2v has a top rep for a 6cylinder.

[Lumpen]

and for the love of God DO NOT SHAVE THE HEAD!

This will only make it hard to start + prone to oveheating!

Been there, done that.

Ooops. My bad

Lumpy