How much power can I make from 260 CI

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
pdq67
Guru
Guru
Posts: 7727
Joined: Thu Mar 04, 2010 8:05 pm

Re: How much power can I make from 260 CI

Post by pdq67 » Fri Feb 02, 2018 10:06 pm

Turborick wrote:
Thu Feb 01, 2018 8:31 pm
We are making 1000hp with a 4.0 x 2.5 SBC with a single turbo @ about 20psi.
hope to end up making 1500hp with 30+ psi
What SBC block are you using?

I think that I have read where stock SBC blocks tend to split the, "V", at 700 to 750 hp. SBF's about the same?

But I don't know at what cubic inch size or at what rpm's?

pdq67

kimosabi
Pro
Pro
Posts: 275
Joined: Sat Feb 22, 2014 5:01 pm

Re: How much power can I make from 260 CI

Post by kimosabi » Sat Feb 03, 2018 9:05 am

A well balanced and very short stroke sbc dont split at 1000hp. I'd be more worried about cap walk.

Turborick
Member
Member
Posts: 122
Joined: Sat Aug 29, 2009 10:43 pm
Location: Palmdale, Ca
Contact:

Re: How much power can I make from 260 CI

Post by Turborick » Sun Feb 04, 2018 11:13 am

pdq67 wrote:
Fri Feb 02, 2018 10:06 pm
Turborick wrote:
Thu Feb 01, 2018 8:31 pm
We are making 1000hp with a 4.0 x 2.5 SBC with a single turbo @ about 20psi.
hope to end up making 1500hp with 30+ psi
What SBC block are you using?

I think that I have read where stock SBC blocks tend to split the, "V", at 700 to 750 hp. SBF's about the same?

But I don't know at what cubic inch size or at what rpm's?

pdq67
I use a GM 24502503 race block. GM rates it to 700+hp
https://www.summitracing.com/parts/nal-24502503
we spin it to 9500rpm
Rick Yacoucci

Nebulous Theorem III.V
http://www.bonnevillestreamliner.com

Turborick
Member
Member
Posts: 122
Joined: Sat Aug 29, 2009 10:43 pm
Location: Palmdale, Ca
Contact:

Re: How much power can I make from 260 CI

Post by Turborick » Sun Feb 04, 2018 11:14 am

kimosabi wrote:
Sat Feb 03, 2018 9:05 am
A well balanced and very short stroke sbc dont split at 1000hp. I'd be more worried about cap walk.
So fare no cap walk at 9500
Rick Yacoucci

Nebulous Theorem III.V
http://www.bonnevillestreamliner.com

kimosabi
Pro
Pro
Posts: 275
Joined: Sat Feb 22, 2014 5:01 pm

Re: How much power can I make from 260 CI

Post by kimosabi » Sun Feb 04, 2018 4:19 pm

Turborick wrote:
Sun Feb 04, 2018 11:14 am
kimosabi wrote:
Sat Feb 03, 2018 9:05 am
A well balanced and very short stroke sbc dont split at 1000hp. I'd be more worried about cap walk.
So fare no cap walk at 9500
2.5" stroke and properly balanced can take alot of rpm. Sounds like a sweet running engine.

Turborick
Member
Member
Posts: 122
Joined: Sat Aug 29, 2009 10:43 pm
Location: Palmdale, Ca
Contact:

Re: How much power can I make from 260 CI

Post by Turborick » Mon Feb 05, 2018 1:50 am

kimosabi wrote:
Sun Feb 04, 2018 4:19 pm
Turborick wrote:
Sun Feb 04, 2018 11:14 am
kimosabi wrote:
Sat Feb 03, 2018 9:05 am
A well balanced and very short stroke sbc dont split at 1000hp. I'd be more worried about cap walk.
So fare no cap walk at 9500
2.5" stroke and properly balanced can take alot of rpm. Sounds like a sweet running engine.
this is what is sounds like
https://www.youtube.com/watch?v=WJCvhoXcPDo
Rick Yacoucci

Nebulous Theorem III.V
http://www.bonnevillestreamliner.com

pdq67
Guru
Guru
Posts: 7727
Joined: Thu Mar 04, 2010 8:05 pm

Re: How much power can I make from 260 CI

Post by pdq67 » Tue Feb 06, 2018 6:17 am

Will 4-bolt main, 400 block engine built to 4.155" b x 3.00" s = 325" handle this kind of power and rpm?

Or should 8,000 rpm be about it. I have a 2-bolt main block too that I can use if the 4-bolt block isn't OK?

pdq67

kimosabi
Pro
Pro
Posts: 275
Joined: Sat Feb 22, 2014 5:01 pm

Re: How much power can I make from 260 CI

Post by kimosabi » Tue Feb 06, 2018 6:56 am

pdq67 wrote:
Tue Feb 06, 2018 6:17 am
Will 4-bolt main, 400 block engine built to 4.155" b x 3.00" s = 325" handle this kind of power and rpm?

Or should 8,000 rpm be about it. I have a 2-bolt main block too that I can use if the 4-bolt block isn't OK?

pdq67
Do you know the cylinder wall thickness? He's talking about a 1000hp 2.5" stroke sbc = alot of cylinder pressure, but it's a virgin bore Bowtie race block.

pdq67
Guru
Guru
Posts: 7727
Joined: Thu Mar 04, 2010 8:05 pm

Re: How much power can I make from 260 CI

Post by pdq67 » Tue Feb 06, 2018 9:28 am

No.

pdq67

MichaelThompson
New Member
New Member
Posts: 38
Joined: Thu Feb 15, 2018 9:25 pm

Re: How much power can I make from 260 CI

Post by MichaelThompson » Fri Feb 16, 2018 9:50 pm

Hi I've been reading through with great interest and learning a lot. I wish you the best of luck with your project.

I realize you have chosen a platform and a very good one it will be I'm sure.

My first thought though when I saw the title that a 8.2" deck Ford is perfect for such a combo, at least to my untrained mind.

The reason I thought this is because, uniquely, Ford is the one manufacturer that coordinates deck height, crankshaft stroke, and rod length to the target cubic inch range.

Yes Ford has taken crap from the magazine guys over the years for the different intake manifold widths due to different deck heights but the rest of the story was never filled in.

The other great things about the little Fords is they're common and relatively cheap, the rotating assembly is very small and light and the camshaft is big diameter and high up in the block. Bigger lifters too.

Short connecting rods to go with a short stroke, and short stiff pushrods and valve train.

jet1
Pro
Pro
Posts: 377
Joined: Tue May 22, 2012 1:11 pm
Location: Alberta

Re: How much power can I make from 260 CI

Post by jet1 » Thu Mar 01, 2018 11:38 am

Interesting as one of my good friends actually has built a sbf based off a 302 in at 260 ci twin turbo for salt flats racing. He is the current world record holder for his class as of last year. He has suggested to me that I should go with the Ford also. The only reason I have been stuck on the LS is that I am very if the project di not work it is very easy for me to drop in a ct525 or LSX 454 and it will still fall right into a class.

jet1
Pro
Pro
Posts: 377
Joined: Tue May 22, 2012 1:11 pm
Location: Alberta

Re: How much power can I make from 260 CI

Post by jet1 » Thu Mar 01, 2018 11:42 am

One issue that I may run into is with the rod ratio. the tall deck height(for this stroke) will make it so I have to use a longer rod than perfect. The most common would be a 6.125 rod but that gives me alot of piston above the rod making the piston top heavy. What are guys thoughts on the rod ratio and pin placement in the piston?

blykins
Guru
Guru
Posts: 2027
Joined: Mon Aug 27, 2007 9:59 pm
Location: Louisville, KY

Re: How much power can I make from 260 CI

Post by blykins » Thu Mar 01, 2018 12:55 pm

They don't matter.

Make the piston as light as possible. There are SBC rods in lengths of 6.250", 6.400", etc.
Lykins Motorsports
brent@lykinsmotorsports.com
www.lykinsmotorsports.com

jet1
Pro
Pro
Posts: 377
Joined: Tue May 22, 2012 1:11 pm
Location: Alberta

Re: How much power can I make from 260 CI

Post by jet1 » Thu Mar 01, 2018 2:26 pm

Well at some point it must matter. I could go to a 6.25 or 6.3 rod but the rod ratio gets up there making the dwell time at TDC longer pushing it closer to det.

blykins
Guru
Guru
Posts: 2027
Joined: Mon Aug 27, 2007 9:59 pm
Location: Louisville, KY

Re: How much power can I make from 260 CI

Post by blykins » Thu Mar 01, 2018 2:59 pm

I don't think detonation would be the issue, I think the issue would be pulling on a big port at lower rpms.

I have ran a 6.400" rod with a 3.500" stroke and 9.200" deck at 8500 rpm. No issues there. May be worth a shot for you...
Lykins Motorsports
brent@lykinsmotorsports.com
www.lykinsmotorsports.com

Post Reply