H'what? 440 build or something
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Thread Starter
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
It still flows 370+ with a 262cc port and a 2.125" valve. Which was good enough for Thompson to hit 782HP with a hydraulic roller on a 427. I think it'll be fine. It's a very efficient port when combined with the 11-degree valve angle.
TECH Addict
Joined: Sep 2010
Posts: 2,898
Likes: 467
I have a head related question that some of you may be able to answer.
I certainly am not sure of anything definitive.
In regards to my heads, I posted some pics of them a while ago in these forums if some of you remember and after speaking to the porter that did the work I found out some interesting information.
The intake port only got a mild clean up and not polished and more work was done to the exhaust side.
I am told hogging out the intake port makes the engine feel lazier down low as it's already quite large.
Plus the rougher finish promotes more air flow as opposed to a smooth finish.
I don't know what way is better as I am not a head expert.
All other places have a nice mirror smooth finish such as Jakes above.
However, all I know is my heads are making great power for the combination I have.
505rwhp with a measly 236/244 114 LSA cam in a 408 stroker through a 3200rpm stall and 3:91 gears.
https://ls1tech.com/forums/generatio...8-stroker.html
Would be good to get some feedback
I certainly am not sure of anything definitive.
In regards to my heads, I posted some pics of them a while ago in these forums if some of you remember and after speaking to the porter that did the work I found out some interesting information.
The intake port only got a mild clean up and not polished and more work was done to the exhaust side.
I am told hogging out the intake port makes the engine feel lazier down low as it's already quite large.
Plus the rougher finish promotes more air flow as opposed to a smooth finish.
I don't know what way is better as I am not a head expert.
All other places have a nice mirror smooth finish such as Jakes above.
However, all I know is my heads are making great power for the combination I have.
505rwhp with a measly 236/244 114 LSA cam in a 408 stroker through a 3200rpm stall and 3:91 gears.
https://ls1tech.com/forums/generatio...8-stroker.html
Would be good to get some feedback
Thread Starter
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
You're starting with a stock LS3 head. It's already a big port and a large valve. Hogging it out further doesn't do much.
As far as the rough finish... what you see are the CNC marks on the aluminum in mine. It looks "shiny" but it's just machined. There's some hand blending in the valve to the port. But most everything is shaped by the CNC machine.
As far as the rough finish... what you see are the CNC marks on the aluminum in mine. It looks "shiny" but it's just machined. There's some hand blending in the valve to the port. But most everything is shaped by the CNC machine.
You're starting with a stock LS3 head. It's already a big port and a large valve. Hogging it out further doesn't do much.
As far as the rough finish... what you see are the CNC marks on the aluminum in mine. It looks "shiny" but it's just machined. There's some hand blending in the valve to the port. But most everything is shaped by the CNC machine.
As far as the rough finish... what you see are the CNC marks on the aluminum in mine. It looks "shiny" but it's just machined. There's some hand blending in the valve to the port. But most everything is shaped by the CNC machine.
This head will do all of what's needed as is.
272cc compared to Frankenstein at 290cc or so , time will tell
Thread Starter
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
Should have my rotating assembly on Tuesday.
Went a little different direction than what I said earlier in the thread.
Did the K1 Crank and Rods with Wiseco Pistons and 4.185" bore.
I did that because I'm not spinning over 8000. Plan for about 7500. Which is about 5000 fps with a 4" stroke. About the max I want to run and should be fine with the K1 crank.
And I decided I didn't want to add 120+lbs to the nose of the car. So with the Darton Sleeved Gen IV, I could run the CCW crank, but then I couldn't run some of the crank scraper and windage trays which would help with windage at 6000+ RPM. So it was a little bit of a give and take but ultimately went to the Darton Block since this is strictly NA. I wanted to maximize the bore and displacement with a 4" stroke... giving me a 440.
Had I pulled back to a 4.155" bore, I could have done a 434 and left open the possibility of some nitrous or something down the line. Or a rebuild. But I knew I wasn't really going to do anything like that--I left all that alone to build an NA motor. FI will be a different car without A/C or a big stereo. Etc. So once I settled on a 4" stroke and the block, I just got the right rotating assembly for my needs.
The heads I have may be a little small for it... but this is going to primarily be a street car. So I think I'll live with giving up 20-40HP at 7500 for better throttle response throughout the range. Plus, these heads were still good enough to push a 427 to 782HP at 7800. If anything, they'll be able to breathe a little more here until the FAST chokes them. So that may be something I look at in the future--the LODSpeedworks X1 or something...
Went a little different direction than what I said earlier in the thread.
Did the K1 Crank and Rods with Wiseco Pistons and 4.185" bore.
I did that because I'm not spinning over 8000. Plan for about 7500. Which is about 5000 fps with a 4" stroke. About the max I want to run and should be fine with the K1 crank.
And I decided I didn't want to add 120+lbs to the nose of the car. So with the Darton Sleeved Gen IV, I could run the CCW crank, but then I couldn't run some of the crank scraper and windage trays which would help with windage at 6000+ RPM. So it was a little bit of a give and take but ultimately went to the Darton Block since this is strictly NA. I wanted to maximize the bore and displacement with a 4" stroke... giving me a 440.
Had I pulled back to a 4.155" bore, I could have done a 434 and left open the possibility of some nitrous or something down the line. Or a rebuild. But I knew I wasn't really going to do anything like that--I left all that alone to build an NA motor. FI will be a different car without A/C or a big stereo. Etc. So once I settled on a 4" stroke and the block, I just got the right rotating assembly for my needs.
The heads I have may be a little small for it... but this is going to primarily be a street car. So I think I'll live with giving up 20-40HP at 7500 for better throttle response throughout the range. Plus, these heads were still good enough to push a 427 to 782HP at 7800. If anything, they'll be able to breathe a little more here until the FAST chokes them. So that may be something I look at in the future--the LODSpeedworks X1 or something...
TECH Addict
Joined: Sep 2010
Posts: 2,898
Likes: 467
Still a good direction.
It's a good idea to keep the engine safe at about a 7500rpm rev limit.
We have a very similar camshaft specification too and we are both using the fast 102 with mid length runners.
Same headers and a dual 3 inch exhaust and a 3800 converter.
The heads are a bit small but you should have great velocity at all rpm's.
I am guessing my engine might pull a bit higher than yours as I have a 2.5 degree later IVC but the same EVO opening.
Even our overlap is intake bias by about the same amount of degrees. And we have the same amount of total overlap at 20 degrees. (Once camshaft is warm)
My compression is also going down to about 12:1.1 too so we can get more timing into it.
Also, I believe your combination will benefit from that new FAST LSXHR manifold.
Its finally available.
Looking forward to seeing how yours turns out.
It's a good idea to keep the engine safe at about a 7500rpm rev limit.
We have a very similar camshaft specification too and we are both using the fast 102 with mid length runners.
Same headers and a dual 3 inch exhaust and a 3800 converter.
The heads are a bit small but you should have great velocity at all rpm's.
I am guessing my engine might pull a bit higher than yours as I have a 2.5 degree later IVC but the same EVO opening.
Even our overlap is intake bias by about the same amount of degrees. And we have the same amount of total overlap at 20 degrees. (Once camshaft is warm)
My compression is also going down to about 12:1.1 too so we can get more timing into it.
Also, I believe your combination will benefit from that new FAST LSXHR manifold.
Its finally available.
Looking forward to seeing how yours turns out.