21 replies to this topic

[Cooperman]

I would guess at between 90 bhp and 100 bhp at 6400 rpm. If you are going for forced induction you will need to re-spec the carb, probably the cam and get different pistons. Presumably your are going to use P21253 pistons, although they will be right on their limit for the sort of revs you'll be using to get the best out of a 286 cam which only works well from about 5000 to 7000 rpm. You will also need a lightened flywheel, a centre main bearing strap and a lower final drive ratio - certainly no higher than 3.44:1 and possibly 3.76:1.

[mini13]

agree with above.

take a step back and decide what you want from the motor before you proceed, personally i like the forced induction /turbo route, but its an individual choice.

[Marlin]

I was thinking this was going to be fairly straight forward. Not so much.
What sort of hp can I expect if I go the supercharger route instead of of using the Weber and 286 I already have?
Can I still use the weber with the supercharger? I have seen them in pictures with the seperchargers?

The guy I am dealing with here says you can get about 150hp out of a fairly stock 1275 with the supercharger kit. Seems a bit high to me. is that anywhere close to reasonable?

[mini13]

150hp is a little optimistic, i'd say more like 130-140hp.... but the rollers might say 150... they are often .....optimistic.

I'm not a big fan of the charger kits as they suck the fuel through the charger so you cant ad an intercooler, quite a few people have ricged chargers up on the front of the engine so they blow through the carb and intercooled them with good results, ie 150+ hp. Also using somting other than the eaton charger is a good move as its only really good up to about 10psi...

another posibility is using the 286 with a charger, you can get away with this on a charged lump and it'll make good power, but it will be thirsty, but super charged engines are anyway.

you can use the weber on the charger, I don't think the improvement is drastic though.


another thing to consider is the gearbox, I wouldnt put much over 130 hp through a std box and expect it to live long although some get away with 150hp.... depends on the drivers mechanical sympathy.

[Marlin]

150hp is a little optimistic, i'd say more like 130-140hp.... but the rollers might say 150... they are often .....optimistic.

I'm not a big fan of the charger kits as they suck the fuel through the charger so you cant ad an intercooler, quite a few people have ricged chargers up on the front of the engine so they blow through the carb and intercooled them with good results, ie 150+ hp. Also using somting other than the eaton charger is a good move as its only really good up to about 10psi...

another posibility is using the 286 with a charger, you can get away with this on a charged lump and it'll make good power, but it will be thirsty, but super charged engines are anyway.

you can use the weber on the charger, I don't think the improvement is drastic though.


another thing to consider is the gearbox, I wouldnt put much over 130 hp through a std box and expect it to live long although some get away with 150hp.... depends on the drivers mechanical sympathy.

What do you mean by a charged lump? I like the idea of being able to use the 286 I already have.

[Turbo Phil]

Charged = Supercharged
Lump = Engine

[mini13]

Ah yes,

a bit of English terminology there!

as with most things someone will have don similar before.... I found this on youtube.