Boring over .015

[spdy3961]

I saw a thread on here that said boring .015 over would be safe and it would put it at a nice 342. I think the gt500 has a 330 in it. Would the gt motor in this case be better than the gt500 b/c it is aluminum instead of cast iron?

 

[08GOGT]

I think you did not understand the thread. I'm guessing it was the thread on the boss 5.0L modular block. If that is the case the block is Iron, it is 5.0L not 4.6L. And a increasing the bore will not make it larger displacement then a gt500 which has a 5.4L block on its own. To increase the cubes by any decent amount you would need to use a stroker kit as well.

 

[ChevyKiller]

I beleive the GT500 motor is about 320ci.

The new FRPP big bore block is a 4.6 actually. It is just much beefier and utilizes custom sleeves but it is technically a 4.6 none the less - but yes, it is an iron block, but I think it's a little lighter than the romeo. Yes, a stroke is invloved to it's not just a matter of the pistons. I'm doing a .015 over diamond pistons on theis block but am also having to replace the rods, crank, and just about everything else too. It's a complete motor build to get the 342'ish cubes. The set-up will definitely put out more power than the GT500 motor.

 

[Kevin@PMP]

I beleive the GT500 motor is about 320ci.

5.4 = 330

 

[ChevyKiller]

TY - noted..

 

[Forward Performance]

.015 over in a 4.6 or 281 = 296

 

[Kevin@PMP]

.015 over in a 4.6 or 281 = 296

No it doesn't.

4.6/5.4 Stock bore = 3.552
4.6 Stock Stroke = 3.554

.015 over 4.6 = 3.567 x 3.554 stroke = 284

It takes a stroker or big bore to get to 296 cid.

 

[spdy3961]

what does a stroker kit come with that gives it more cid? I am a newbie at auto parts lol

 

[SoundGuyDave]

A "stroker kit" comes with new pistons, rods, crank, and the other small bits (like bearings, wrist-pins and rings). The kit usually has shorter connecting rods, and the crank has the rod throws further away from centerline than the stock crank. As it rotates, these throws cause the piston and rod assembly to travel a longer distance, thus giving a larger stroke dimension. HTH.

 

[Kevin@PMP]

Just like Dave said, a standard stroker crank for a 4.6 is a 3.75" crank, the Saleen PJ's use a 3.8" crank.

 

[US-1]

For those of you who do not know the formula..........

Bore X Bore X Stroke X .7854 X 8 = cubic inch

Increase the bore or the stroke (or both) and you increase cubic inches. Pretty simple. The limiting factors are the block. There is only so much material you can remove by boring a stock block. Once that is done your option becomes resleeving the block or using a "big bore" block from FRPP.

With a stroker crank you will also get either shorter connecting rods or a piston with a pin located higher up in the piston. Sometimes both. The limit there becomes how far the connecting rod pulls the piston out of the bottom of the bore at the Bottom Dead Center position.

As stated by others, common stroker crank setups utilize the 3.700", 3.750" or the 3.800" strokes. All of these will put you right at 300" with a stock bore block. With the above formula you can see for yourself. The FRPP big bore block and the Darton Sleeve System will give you a 3.700" bore to work with. Utilizing one of these with a stock stroke crank you will again be in the 300" area.

Put the big bore and the stroker together and you end up in the 323" area. All of this applies to the 4.6 based engines. The 5.4 engine utilizes the same bore as the 4.6 but uses a 4.160" stroke, a much longer connecting rod and a taller deck height block.

Class dismissed. This information will be on the mid-term.

 

[ZmanM3]

Good class!

 

[ChevyKiller]

For those of you who do not know the formula..........

Bore X Bore X Stroke X .7854 X 8 = cubic inch

Increase the bore or the stroke (or both) and you increase cubic inches. Pretty simple. The limiting factors are the block. There is only so much material you can remove by boring a stock block. Once that is done your option becomes resleeving the block or using a "big bore" block from FRPP.

With a stroker crank you will also get either shorter connecting rods or a piston with a pin located higher up in the piston. Sometimes both. The limit there becomes how far the connecting rod pulls the piston out of the bottom of the bore at the Bottom Dead Center position.

As stated by others, common stroker crank setups utilize the 3.700", 3.750" or the 3.800" strokes. All of these will put you right at 300" with a stock bore block. With the above formula you can see for yourself. The FRPP big bore block and the Darton Sleeve System will give you a 3.700" bore to work with. Utilizing one of these with a stock stroke crank you will again be in the 300" area.

Put the big bore and the stroker together and you end up in the 323" area. All of this applies to the 4.6 based engines. The 5.4 engine utilizes the same bore as the 4.6 but uses a 4.160" stroke, a much longer connecting rod and a taller deck height block.

Class dismissed. This information will be on the mid-term.

How is adam figuring I'll have about 342 cubes with the big bore (3.850" {I think} crank, custom wrist pins on .015 over pistons, and I forgot the rods but the point is how is he getting 342 out of the big bore?

 

[US-1]

How is adam figuring I'll have about 342 cubes with the big bore (3.850" {I think} crank, custom wrist pins on .015 over pistons, and I forgot the rods but the point is how is he getting 342 out of the big bore?

THAT is exactly what I would like to know. The bore on the "big bore" FRPP blocks is 3.700". With a 3.750" crank you have 325" on a .015 overbore. With a .010" overbore and a 3.750" stroke you get a 324" engine. Did someone transpose a number? Say....it was supposed to be a 324" engine and somebody's dyslexia kicked in????

When you first stated "342" I racked my brain to come up with a way he was doing this. Figured it was probably a stroked 5.4 engine.

 

[ChevyKiller]

I've got to talk to him on Monday but my understanding is that I'm getting right about 340-342 with a 3.800" crank & .020" overbore with something else relating to the rods as well.

My numbers may not be exact but I know they are in the ballpark and I am also a little perplexed in my understanding of how we are getting the cubes and what exactly the cubes are going to be.

Guess I'll know for sure in a couple weeks...lol All I know is we sent the block out to be tested and Dave came up with the set-up to get me the most I can get out of the big bore block. I am positive he said a stout 340 - so I'll have to get the exact specs to figure out how he is coming up with that number.

Keeping with the math, I also do not see how cali HP is getting a 326 with a .005" over?

 

[US-1]

I've got to talk to him on Monday but my understanding is that I'm getting right about 340-342 with a 3.800" crank & .020" overbore with something else relating to the rods as well.

That would work out to 330". 3.720" bore X 3.800" stroke.

Keeping with the math, I also do not see how cali HP is getting a 326 with a .005" over?

With a 3.705" bore and a 3.75 crank=324" With a 3.800"=327.7 or 328". Somebody spilled beer in their calculator.

 

[ChevyKiller]

Correct. I just got the official numbers and now I understand.

We were HOPING for a 340-360 before the sonic tests. Dave gave me the 342 number based on what he predicted.

After the actual tests and learning exactly have far you can go on this block, the safe max is where I'm at...

Your numbers are about dead on - I'll be at a 330.7x (basically a 331) with a .020 over and cali will be at a 325 with .005 over.

So, at least now I have a definitive number 331ci...lol

Still ain't going to be too shabby...

2 weeks to go for the pistons and we can get this thing togther. Full cage is getting finished off this wekeend....

Adam is right along with you on the cams. We will figure out this week exactly where I can twist this thing and then get a custom set made. I think for the money, best just to have what you want made then to try to work with what's out there. Once I know how how I'll actually be able to turn this thing, it will help nail down the specs for me.

 

[US-1]

I'd go with those custom numbers I gave you. (Now that sounded very self-serving....and wasn't meant to be.) I just like the numbers. The duration is going to be the kicker. Always has been on a modular engine. With that many cubic inches and the KB blower I think the 227/237 with a 114 lsa is going to be tough to beat.

Damn....y'all have me in camshaft mode now.