4.1 vs 109 block

[434nova]

What is the strength of a 4.1 compared to a 109 block. How much hp can it take and how big can a 4.1 be made? Both blocks with caps and girdle. Is 800 hp possible? Thanks

 

[earlbrown]

When you get to that HP level, it's not so much the block strength that's the issue, it's the tune.

 

[Mike Licht]

When you get to that HP level, it's not so much the block strength that's the issue, it's the tune.

X 100

 

[Jay J]

Ok guys. All else equal, with good parts installed and a better than good tune--which one?

 

[Jay J]

Just asking for use in a street car--not full drag race. More cubes, or the tried and true 109??

 

[earlbrown]

For a street car (assuming a good state of tune) there won't be a difference. Blocks don't really 'break', they get broken.

 

[TurboCrazy]

The extra cu. in. from a 4.1 does make a difference on the street. Mid range power always seemed to feel a little stronger.

 

[Mike Licht]

the extra torque from the 4.1 is more fun, it can spool the turbo better and eat up more cam without bottom end loss (within reason)

 

[Howling Mad]

It really comes down to how much you want to spend. A well built 109 or 4.1 can both be a lot of fun on the street. If your building the 109 that's in your car its gonna be a little cheaper. Though in hind sight I sometimes wish I would have built a 4.1 with a stroker but really when am I going to need that much for a street car?

 

[whitehot1]

I couldn't imagine having any more power than my aluminum headed 109 puts out. It sometimes is more than a handful if i'm not paying attention to what i'm doing when driving normal and then get a little aggressive with a ricer or biker.

 

[Nick Micale]

What is the strength of a 4.1 compared to a 109 block. How much hp can it take and how big can a 4.1 be made? Both blocks with caps and girdle. Is 800 hp possible? Thanks

Like many questions here on the board, without being more specific, you can only receive a general answer, and of course MANY opinions?

First, I will assume when you say "800 hp", this will mean engine output, not to the rear wheels?

Second, both blocks share the common weak point that will be the usual cause of failure at that level, and it will be the webs from the cam bore to the main bearing saddle. This you cannot prevent even with a girdle.

Third, you have no mention of how you will use this car at 800 HP, and this would be a mid-9 sec GN? Even at 1/2 that power level, you can seldom use that much on the street, and certainly upgrading the trans and suspension big-time would be required.

My production 4.1 engine is running 9's which is close to 800 HP at the engine, and so far has been doing fine, and I plan on pushing it until it needs a freshen-up or gives up!

 

[6togo]

What's the cost to build a 4.1 and get it close to the 800hp range Ballpark?

 

[earlbrown]

When you start talking about 800hp the price is the price. It doesn't matter if it's a 3.8 or a 4.1 (once the block is done being prepped)

 

[6togo]

So what prepping does a 800hp block get that say a 500hp block don't just curious because none of them are cheap to build?

 

[earlbrown]

By prepping I meant, boring, honing, decking, line boring, deburring, cleaning, cam bearings, freeze plugs, inspecting, etc... There's extra prep like billet caps and/or girdles.


If you truly want to have an engine capable of 800hp (no idea where that number came from) without already knowing how to build, tune, and maintain one, you really need to build one that will handle over 1200HP+. And that is really over the capabilities of a junkyard block.

 

[kidglok]

Has anyone seen a 4.1 crack in the valley area? Just curious


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[Mike Licht]

if you cant tune your over any block

 

[6togo]

I would think Anyone building a 500+ HP block would be adding caps or girdle.

 

[Jay J]

Has anyone seen a 4.1 crack in the valley area? Just curious


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Yes. I had a 4.1 block that I gave to a friend--he over-amped it and that is where it broke. As has been mentioned here earlier, you got to have the tune as well as all the good parts.

 

[earlbrown]

Did it break, or get it get broken?