Sammyboy

Hi all, I wanted some assistance/extra opinions on some crankshafts... I am at the stage with my XC ute project where I am planning on rebuilding my 2V 351 (from an XB) and starting to fix up the body of my ute. I found one guy who can play with my crankshaft on some sort of machine and turn it into a 377 crank. He told me that there would be 20% more power, much more low down torque and virtually the same fuel usage from it. it's only going to cost me a few hundred $$$ more than keeping the crank in it's standard form, so if this is all true, it sounds pretty good to me. I am aiming for 200-250 rwkw. Is there anything I need to be aware of or watch out for? Should I stick to the original 351 crank and forget about the 377? Why? Any help would be much apprieciared. P.S- I have a Holley 750 vac, will be changing inlet manifold (Edelbrock performeror Weiand x-cellarator or something like that), upgrading camshaft, minor work on the heads (not much at all), fitting headers and duel exhausts (maybe 2.25 or 2.5)

mr_460bigblock

sounds like he is going to offset your crank. lot of work and if he is saying only a few hundred more??? can almost gurantee that hundreds will go into thousands. Trust me i know, am going through it now with my 460 build..

Why not look into a stroker kit from scat,eagle etc?

you can get cast or forged cranks, bigger capacity (383ci,393ci,408ci) I or H beam rods etc, think some of the kits come already balanced also.

It entirerly up to you of course, but if it was me id go the stroker kit, i wouldnt worry about what the builder is gunna do, not when there are so many easier options out there and it may cost a few pennies more for the kit, but, you will pay less in labour at the engine shop.... offsetting cranks takes time!

If you wanted to keep it standard 351 in size, im sure with all the new manifolds/heads/cams etc, you should be able to get close to the power you want from the 351

I cant see any dramas with you using a 750 holley, inlet manifold i (think) the edelbrock performer is a dual plane? the weiand X is a single? anyway if its low down torque you want, go a dual plane manifold, if its more top end hp your after then sacrific a little torque down low and get a single plane manifold.

what sorta work on the heads are you wanting and what cam you thinking? (specs?)

__________________
A wise man once said about an old mountain: "There is no Substitute for cubic inches...."

Some countries have Volcano's, One has Everest, We have Mount Panorama.... The Greatest Mountain of them ALL

466ci / Tremec TKO600. Be back on the road soon...

1BADSS

If you want to get 250rwkw, you will need to spend some money on getting the heads ported and not just a little. My old XY put out 255rwkw with a standard stroke 351C, 750 Speed Demon, 1" open spacer, Weiand X-cellarator, Crane F-246, ported 2V heads with 4V valves and KB flat tops, running 10.5 Comp. I'd spend your money on the heads not the crank to get the power you are looking for.

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That is a sweet noise you got there man, I had you picked clear across the valley............

'headbang'

russxr67

With the availability of aftermarket cranks these days it DOES NOT make sense to spend the money on altering the factory crank .

You can buy new cast cranks for less than 300 bucks. The machining on your existing crank will cost more than the price of a new crank. I have a sub 300 dollar crank in my 383 and it made over 550 hp. A lot of guys were telling me that my cast crank won't live to see the dyno session out.They all ate humble pie that evening.

You can also buy a set of rods to suit these cranks for under 350 bucks as well. They are chev rods but keep in mind that MOST of the aftermarket clev cranks are machined specifically for a CHEV rod.

A good set of slugs will be the most expensive item in a stroker cleveland. Most of the big names in piston manufacture have something on the shelf to suit the various stroke/rod length combo's.

1BADSS is right in saying that you need to spend some money on the heads. Make no mistake,the cylinder heads are the lungs of the engine. If they cannot supply the goods you will not realise the full potential of the engine. Standard heads are poor to begin with IMHO and definately need addressing in some key area's. You don't have to get exotic,you just need to find someone who is well versed in the clevo cyl head.DO NOT fit 4v Intake valves to a 2v head.

If you have a limited budget to work with then you may have to forget the stroker for now,however dollar for dollar it will be the wisest move to make. When doing your comparison of stroker vs standard stroke ,factor in the following.
You will need to have your existing crank reground to undersize spec.
your rods will need to be resized,have ARP bolts installed.
New forged pistons
You will find the cost of the stroker to be comparable to reconditioning your old parts.

Sammyboy

Thanks for your help guys. After reading what you all said, I guess it makes more sense to keep it a 351, save my money and work on the heads. I am unsure of the exact cam that I will use, or the exact inlet manifold, but I will discuss this with the person who build me my engine. I have been quoted prices between $2600 and $8000 for a full rebuild, so it's hard to know where to go....

1BADSS

Why would you say that? it is a tried and true mod to preform on a performance 2v headed Clevo.

You don't need to spend the money on forged pistons, a set of hypereutectic pistons will be more than suitable for the power you are chasing.

__________________
That is a sweet noise you got there man, I had you picked clear across the valley............

'headbang'

mr_460bigblock

[quote=russxr67] DO NOT fit 4v valves into 2v head[\quote]
[quote=1BADSS]Why would you say that? it is a tried and true mod to preform on a performance 2v headed Clevo.[\quote]

i was thinking that myself? i was even told to do it to my 460 heads (which i did )

I think you will find also, a lot of alloy heads, most come standard with 4v size valves, cause when i was talking to a few places for alloys on the 460, all of them come out of the box with 4v size valves

__________________
A wise man once said about an old mountain: "There is no Substitute for cubic inches...."

Some countries have Volcano's, One has Everest, We have Mount Panorama.... The Greatest Mountain of them ALL

466ci / Tremec TKO600. Be back on the road soon...

XB351

not on clevo heads most alloys have smaller than the 4v 2.19 inlet. I know mine arre only 2.1

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XB Fairmont sedan 11.07@123.02mph

russxr67

It is a much used modification that's for sure but that's not to say that it is a wise one.

Have you ever tried to reshape the ssr on a 2v cleveland head?

Do you know how thin they are in this spot?

russxr67

[quote=mr_460bigblock][quote=russxr67] DO NOT fit 4v valves into 2v head[\quote]
First of all you are comparing apples to oranges. A 460 is not a 351 .

The reason most shops fit 4v valves on the intakes is that they are using sheep mentality. They follow the flock so to speak. They are not innovators,they just do as everyone else has done for the last 30 yrs.

And,to set the record straight most aftermarket clev heads have smaller intakes than the 4v size.

mr_460bigblock

i wasnt 100% with clevo heads, most aftermarket 460 heads come with the 2.19inlet (cant think of the 4v exhaust size off the top of my head)

__________________
A wise man once said about an old mountain: "There is no Substitute for cubic inches...."

Some countries have Volcano's, One has Everest, We have Mount Panorama.... The Greatest Mountain of them ALL

466ci / Tremec TKO600. Be back on the road soon...

1BADSS

No I haven't, I leave that kind of work up to the experts.
You still have not enlightened us on why it is a bad mod to do. It seems to me everyone does it because it is a proven worthwhile mod.

__________________
That is a sweet noise you got there man, I had you picked clear across the valley............

'headbang'

russxr67

The answer lies in what was written in paragraph 2 and 3.

You cannot reshape the ssr properly with the 2.19 valve without hitting water.... about 2.1 is the limit but even at 2.07 they can move some air.
the clev head needs surprisingly little work to make it a much better piece.....unlike some heads