All things being equal, how much hp/tq is just the cubes worth?

Worth $400 to upgrade?

 

Won't be so much a displacement factor as it will be your heads/intake choice. Too many other factors involving the rest of the package to make an accurate assessment.

You also wanna decide if you plan on going FI eg. Nitrous or Boost eventually. That can also play a factor in your displacement/block choice.

 

Its around 1.27 hp/ci and I just had this discussion with Barry at Airflo. Again, thats just an average. So a 402 vs a 416 (14 x 1.27 = 17.78hp) would be roughly a 20hp difference. I'm not sure if thats rwhp. I am thinking 440 myself, but then I can only run a 100-150 shot safely.

 

Agreed 110%

 

Well I will stay NA. NO N20 or FI.

I have as cast Trickflow 220cc heads. I'm thinking along the lines of a 236/238 600ish cam. I have an A4. Want as much power as I can get while still ensuring I don't get any surging or bucking with the cam. I have to maintain good street manners.

Not sure I believe the 1.27/ci. That would mean I'd gain 50whp going from 364 to 403. I think most only gain around 17 with the same jump?

 

Then go as big as your budget allows

Barry's displacement-to-power increase calculator that Jay posted is based at the flywheel/crank. Too many different drivetrains, trannys, and rear-end losses to be consistant from set-up to set-up. Still it's a tad optimistic as a general rule of thumb IMHO

 

1.27 is a good rule of thumb...IF....you have a good builder who will match everything properly. Since most builders do not match things properly you can look at about 1 hp/cubic inch.

also, there are 416's out there that idle very very close to stock that are making 530 RWHP through M6's.

 

I'm looking to make 500ish through an A4 with 3.91s with excellent street manners. I have a tripple disc converter that locks up at wot in third so it dynos like an M6.

Does not consume oil and does not smoke. Starts every time and idles fine with a little chop to the lope. Just enough to let someone know something is there.

 

Maybe the OP wasn't referring to matched/upgraded parts

I made my response under the basis that the only change in this particular scenario would be displacement and all accompanying parts transferred.

Calculating and predicting the change in horsepower for different bolt-ons on different displacements/engines would be difficult to say the least.

 

go for the 416. It will make a lil more power and have a lil smoother idle.

 

How would these specs be for a 403/416?

236/238 .601/.605 113 LSA

With Trickflow as cast 220cc heads milled to 61cc?

 

Thats why I said that though. Doesn't sound like he pulled the trigger yet, so he can still make sure his engine, when built, is nicely matched. All else being equal doesn't work when adding cubes, because now you changed what the 402's cam, heads and intake will do on the new 416. That new 416 will be able to take a little more cam, maybe totally different heads to match that new cam, etc....
Its like me going from my current 427ci and simply boring it to make it a 454ci...keeping my same parts...no way I'd net 1.3 hp/cubic inch, it wouldn't be able to breath like a 454ci.

But, to the rule-of-thumb...if a 402 and 416 were built and matched nicely by the same builder...the 416 should make about 1.3 hp per cubic inch over the 402.

A builder like Barry will get that 1.3 hp per cubic inch. He did exactly that when he built a guys 422ci that put down 535 RWHP N/A and 880 RWHP on spray.

 

500 RWHP with a smooth idling 416 will be easy for the right builder, easy. You'll get more though. Cam in the mid 230's. Talk to the guy "Jayplay" is talking to, he's a master with the 416's.

 

The idle will be pretty smooth in 416. The cam I had in the sig had a lumpy idle with good manners. The wider lsa really smooth out the idle. You probably can get the idle you want with a 240 114 cam. Like eveyone sez talk to the engine builder. Us internet experts dont know jack

 

This is encouraging for me... I am building a LS3 - 418 stroker from TSP with a 240/246 .608/.612 cam with 112 LSA carbed Victor Jr. with AFR heads 3500 stall TH350 in a 3100lbs C3 vette.

The internet police say my car will SUX *****

I think I will run 11.1 to 11.0 @ 122-124 even with a 3.36 gear on Drag Radials.

 

that thing is going to be a beast! there is a guy i talk to from time to time where i live that has a 416 with 575rwhp in a c5-Z06 w/ an m6 running like a 10.1 or 10.2. car deff. has high 9's in it, just a matter of getting the right launch and hitting all the shifts.

 

I would hope a AFR headed 418 stalled auto Vette would run low 11's!

 

If you hook, mid 10's for sure.

 

575 RWHP, M6. 416 cubes.

What heads and intake?
Compression?
Race gas?

 

Should I go 42lb or 46lb injectors? I hear a lot of people run 42lbers. I can get 46lb FAST LS2 style injectors for $390. They good injectors and would they be enough/too much for a 416?