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I guess at what's in Nick's engine and used the tuning you gave me and got 588@10400 so close to what you have.
Then a re-tune to 581@9200
Intake length = 17"
cams at 102/110
Primary=31", 1.65/1.875
Collector = 2.8/2.25 x 5"

A touch less hp but Less hp but at a much lower rpm and the torque is higher and a lot wider.....but I guessed at the most important item...the heads....and I'm just now remembering its a 2V isn't it?

Nicks 3.5L was a 2V, the engine we're discussing here is the QV 4L that is now for sale by owner. Nicks new engine is different from this as well., I know always changing

Now see.....the tuning I was talking about was to pull the rpm down on the 10500 engine (Nick's??) not the for sale engine, and I remember you saying there was a special 4v project but I didn't realize it was for Nick. Its only been the last year or so that I think I finally have my head around what exactly I did on my engine and when I open other build files I've been able to see similar results like my estimate of Nick's engine. It could just be I've found a flaw in dynomation but I see VE go up 10-15% with the alternate tuning I've been using.


The for sale engine I wouldn't have even a guess at and it really doesn't matter because it's done and for sale

OK, lets try more useful info... posting before finishing my tea, never a good idea..

this is the 4L currently up for sale vs Nicks new build that has ITB's and heads that flow substantially more. I've kept the cam profile and exhaust setup between them the same. I've got another cam option I'm playing with but so far this one is working great. Nick keeps vacillating with the idea of adding boost, so it's a moving target some weeks..

ok here's Nicks build as is and with the notes you've made about cam and exhaust. On Nicks 308 his muffler sports twin 3" inlets. So the tri-Y would need to merge to 3". Space is also a consideration, not sure how one would stuff 31" of primary into that engine bay as the stock length is already sporting a pile of turns.

Boom!

I don't know if it works on real engines but dynomation loves this tune.

It doesn't matter how big you want/need to go on exhaust pipes. My collector out is 2.37 and I have 3.5 out pipe. That choke/merge point is important though, it effectively terminated the collector and it's pulses, without it your entire exhaust becomes part of the collector.

On length you were 22+8.5 = 30.5", this is 31+5= 36......it doesn't take much loop in the pipe to make that up. I roughed mine in with pipe insulation with an alum welding rod inside so I could quickly see what was possible and what was not.

Below is the burns design for my engine, you can see the merge/choke and how the tri-y is created/modeled. Note those are the header tube lengths, you need to add the port length

Here's what the High-low overlay for the tri-y looks like on my estimation

for low rpm I used
Primary =23.5, 1.65/1.65
collector = 12.5, 3.00/2.25

The 4500 dip is all filled in....in theory anyway

I like that collector layout, thanks!
It has me re-working cam timing again... thanks I guess...

The only difference here is the cams, the peaky one is the profile similar to yours, the one with more bottom/mid is a modified 288 profile. hmmm... exhaust specs as you noted above.

Be sure to look at both the high and low rpm header configuration when playing with the cam because the headers generally fix the 4500 dip you see on the "peaky" cam. I found the intake seems to work well in the 102-104 range and exhaust in the 108-112 range with this tuning on my setup and yours look similar so I'm guessing you'll find the same.

Long ago I played with adding a variable intake and going down to 95-98 seemed good if I could swing it back to 104-108 for high rpm....if you want to add more parts to the build that is

Yep noticed the same thing. The QV and the V12's seem to share that similarity, didn't see that on the 2V V8's.

Was looking thru the old 275/365 V12 data and the cam timing there is interesting...

275 GTB
18
56
56
18
I & E CL 109/109

275 GTB/4
45
65
60
41
I & E CL 100/99.5

365 GTB/4
45
46
46
38
I & E CL 90.5/94

365 GTC/4
43
38
38
34
I&E CL 87.5/92
All have an LSA of 98.25