I have a 351w bored 40 over. Stock bottom end, all arp bolts. I have a vic jr single plane intake, trick flow stage 3 hyrdraulic roller cam, trick flow 1.7 rocker arms,so cam will be 640 lift do not know the other specs of cam off hand right now, trick flow twisted wedge 11r 205 cylinder heads, 56cc combustion chamber, trickflow track max valve springs for larger cam lift, forged pistons with valve reliefs should be right around 11.1 compression, all msd ignition 6aL box, holley efi sniper carb. With 1 3/4 long tubes what kinda power should I expect or what would you change on the combo not worried about drivability. Shooting for atleast 450 to the motor! Do you think that is possible with this combo I have? it's not running yet getting ready to put the top end together just wanting some of your opinions before I unbox everything and put it together in case theres a more thought out combo you guys may have experience with. Also what kinda numbers have you guys gotten with your 351w builds and what parts did you use?
351w na build combo opinions
- Thread starter Dan gibson
- Start date
-
Sponsors (?)
This is another one of those threads, that pops up from time to time, that I don’t completely know the answer too. While all your parts sound pretty healthy, but I can’t give you an educated guess, but because I’m curious, I’ll ask a guy (or guys) that can rattle off some good info
@FastDriver @90sickfox
If they have time-they will drop in
@FastDriver @90sickfox
If they have time-they will drop in
Steel1
Mustang Master
Yeah , that should be a pretty stout combo.
If possible keep us posted on what kind of power it makes.
If possible keep us posted on what kind of power it makes.
I'm not a carb guy, and I would always go with a custom cam, but the heads, displacement, and lift can get you there. The question is whether or not you're going to run out of RPM on that cam or on the limitations of the rotating assembly first. Sorry that I can't give a good recommendation on a carb, but those are the right heads, IMO. It should rip. I'm assuming a manual trans, but if it's auto, it can look like less power on the dyno than it will run like at the track.
With those heads on pump gas you will want to set timing around 28-29* at wot. Trust me when I say you will see a drop off in power above that point, the 11r head is not like most sbf heads and excessive timing will hold you back. Even lower comp wont like much over 29*
Each engine is different but this has been my finding from a few builds.
Each engine is different but this has been my finding from a few builds.
Ok thanks that's good to know, I will be sure to try that when getting it all tuned in!
Hey man!
I believe that combo will exceed your 450hp mark by a huge margin; In fact I think 540+ is not out of the realm of possibility...those heads just flat rock n' roll. That being said, I would fear that it may happen at a far more lofty rpm than a stock bottom end is gonna like continuously. Just bench racing here based on past builds of course, but I'd be willing to bet that combo won't start making good power until 3k or later with less than 360 cubes pumping air, and is going to want to pull to the moon...or I mean at least until the limits of hydraulic lifter control. Furthermore, with that hairy of a cam, a guy really needs at least another full point of static comp to keep your cylinder pressure in the sweet zone. That is if I'm looking at the right grind of course. In short, it looks like this is one of those builds that could be optimized either way with just a couple of parts changed. Like either go with a nice light aftermarket crank and rods, bump the comp up a bit, and go ahead and twist it to seven+ and make 600+hp, OR... back off a whole bunch on cam, dual plane it, and enjoy a big gob of upper mid-range and throw in the towel at about six so she'll live forever. Also, I HATE to even go here, because it's such a typical response from the whole "dude, go bigger everything" camp, but there's no denying of course that 408+ cubes would gobble up all that air nicely and likely live a long and happy life twisting to 6500-ish, too...just something else to consider if you're not completely against the idea of a stroker motor, sir. One thing about it, you've got some major [email protected]$$ parts in the pile; those heads are awesome, AND you're gonna LOVE that Sniper set-up when it's all dialed in...the response on a good combo is insane, and it's really nice to be able to just bump the key and walk away, even on a pretty aggressively cammed motor. I know I wouldn't give mine up for nothin'! As stated before, please keep us posted; I'll be dying to know how that bad larry runs...you should be happy no matter what! Best of luck on a smooth build, and happy wrenching, bud!
I believe that combo will exceed your 450hp mark by a huge margin; In fact I think 540+ is not out of the realm of possibility...those heads just flat rock n' roll. That being said, I would fear that it may happen at a far more lofty rpm than a stock bottom end is gonna like continuously. Just bench racing here based on past builds of course, but I'd be willing to bet that combo won't start making good power until 3k or later with less than 360 cubes pumping air, and is going to want to pull to the moon...or I mean at least until the limits of hydraulic lifter control. Furthermore, with that hairy of a cam, a guy really needs at least another full point of static comp to keep your cylinder pressure in the sweet zone. That is if I'm looking at the right grind of course. In short, it looks like this is one of those builds that could be optimized either way with just a couple of parts changed. Like either go with a nice light aftermarket crank and rods, bump the comp up a bit, and go ahead and twist it to seven+ and make 600+hp, OR... back off a whole bunch on cam, dual plane it, and enjoy a big gob of upper mid-range and throw in the towel at about six so she'll live forever. Also, I HATE to even go here, because it's such a typical response from the whole "dude, go bigger everything" camp, but there's no denying of course that 408+ cubes would gobble up all that air nicely and likely live a long and happy life twisting to 6500-ish, too...just something else to consider if you're not completely against the idea of a stroker motor, sir. One thing about it, you've got some major [email protected]$$ parts in the pile; those heads are awesome, AND you're gonna LOVE that Sniper set-up when it's all dialed in...the response on a good combo is insane, and it's really nice to be able to just bump the key and walk away, even on a pretty aggressively cammed motor. I know I wouldn't give mine up for nothin'! As stated before, please keep us posted; I'll be dying to know how that bad larry runs...you should be happy no matter what! Best of luck on a smooth build, and happy wrenching, bud!
So after a way longer time than expected I got the engine on the dyno the other day. It was a dts dyno. It was 90 plus degrees outside and pretty humid. It made good power but not what I had expected. It put down 470hp and max tq was 440 at 5300rpm. It made its Max hp at 5800rpm with a 13.32 afr. He said the lifters and valve train were not floating. I don’t understand why he didn’t rev it to 6800rpm, like the cam and heads and intake are all good up up to. The dyno chart goes to 5900rpm but the power drops off by like 6hp. I’m not sure if that’s just where he let off or not. But I feel like it should have revved way higher and been over 500hp. What are your thoughts I know everyone thinks there motor should make more, but I don’t understand why it didn’t rev higher or if that’s just when he let off. I will get more details next time I talk to him when I pick it up. I know he mentioned he didn’t think i should rev it higher since it’s hydro lifters but I’ve reved a 331sbf with the same lifters to well over 6500rpm.
If the guy saw the power curve start to fall off above a certain RPM, there wasn’t any point of revving the engine any higher.
Depends .. cylinder to cylinder you can have up to a full point afr spread. Port injection usually holds this down lower about. 5 of a point.. at 13.3afr the leanest cylinder could be seeing 13.8afr...
You see the issue here, power falls off hard. What was the timing? Was latency checked? Did the timing fall of with rpm (latency). Did the curve have a slightly rising timing value? Ect
You see the issue here, power falls off hard. What was the timing? Was latency checked? Did the timing fall of with rpm (latency). Did the curve have a slightly rising timing value? Ect
Believe he said timing was at 32. I am getting the motor tomorrow so I will ask these questions. Thanks
An 11r head with 11:1 comp ratio... Depending on the fuel it may be over timed. Every 11r build on pumpgas I have done makes best power at 27-29* the 11r head is very efficient
Similar threads
