Please help me understand this,How in the hell did Tony get all that HP/TQ is his car at only 383ci's,while a lot of 408ci guys are having trouble even hitting 525HP.Tony's 383ci is sure impressive!!!!I dont see why a 408ci can't easily achieve that or even better.Theres a lot of high HP/TQ 408ci here,but not as impressive as Tony's,What gives?I know HP does'nt mean alot sometimes,but just wondering.How do u maximize all the possible torque under the curve like Tony's gragh staight as a level?Has anybody found the magic TQ monster cam yet for a 408ci?

 

well his 383 was a solid roller so keep that in mine. Plus you got to remember that he prolly spent A LOT of time dialing it in perfrect.

Justin

 

thats because tony has et240s









just joking

 

heh...A&A corvette sold their old dyno and bought the one they have now because it "gives higher #'s, so as to be on par with the other shops around the country with optimisiticly high dyno #'s..." straight from the owners (andy's) mouth. Not saying they are fudged #'s but they are definately going to be as solid as they can possibly be.

 

yeah there was something wrong with andy's old dyno, but andy's new dyno definitely doesnt read high, i find it right about accurate with comparable dynos

 

from the video i have seen showing his vette, i don't believe they are blowing the numbers out of proportion.

 

also i think that they spend a lot and i do mean a lot of time tuning that car.. most of the people pay for a tune and never get as much time on the dyno like they do.. sometimes its the tune that doesnt help

 

His setup is well matched. He did try several different combos and went with the one that put down the most horsepower.

Most people overcam, underhead, and poorly match their components on head/cam packages and 408s. That's why you see **** poor results often.

For example, a 248/254 114 cam is way too big for a 408. On a 112 it'd be better suited for a 427. And I'm not talking drivability--that's later. I'm talking optimum valve events (VEs). The cam should make peak power at where the manifold forces our engines to peak ~ 6300rpm. Trying to peak higher than that gives diminishing returns and softens the midrange.

The reason for doing this? Drivability. Nobody wants to run a 248/254 on a 108 or 106 in a 408, because it's too much overlap. But it forces the DCR up and keeps the peak near 6300 while creating area under the curve. Keeping the cam on a 114 and advancing the cam will cause the power to fall off quickly after 6300, whereas the 108 or 106 will carry it to 6800-6900 easily. So it's better to just grind the cam with a much narrower LSA, but again, that creates a lot of overlap.

A better cam would be a 238/242 112 in a 408. It'll make nearly the same peak power as the 248/254 114, but it'll produce a lot more average power and provide even better drivability, because it has lower overlap and optimal VEs.

With that said, Tony's combos always go for a smaller camshaft that better takes advantage of the high flowing heads. If you've ever seen results from an MTI 427, you know they make 550rwhp with a 236/236 cam. The heads flow well and they decided not to overcam it. Lingenfelter is the same way.

 

What would be optimal valve events for a 408ci,I heard Patric G mentioning something to this effect a while back.Theres a certain limit as far in derees is concerned that should not be overdone,have great DCR and have more usable HP/TQ under the curve.

 

after seeing the power the Futral cars make, im gonna have to disagree with you there

as for Tony, he has a lot of little special touches that most people just dont bolt on that can account for 20-30 hp

 

Futral cams have a ton of advance also. So the cams don't appear as big as they are in terms of VEs and the lobes are usually fairly lazy, so again the numbers at .050" don't tell the whole story as to why those packages make a ton of power. Compression is the other piece to the puzzle. People are afraid to run compression with big cams (thus they get half-assed results), but not Futral. He knows his ****.

For a 408, I'd go 243/247 Comp LSK on a 110+1. The overlap is no worse than a T-Rex but it's lobe lift after .050" is far more aggressive. The lobes specs are as follows:

Lobe#, Dur. @ .006", .050", .200", & Lift
2131 293 243 168 .653"
2132 297 247 171 .656"

 

Jake Fusion...your responses sound very thought out, articulated and completely wrong.

Futral and several others would sharply disagree.

 

Futral's lobes are not lazy.

 

FAST LSX90 restricts the peak RPM to 6300. Set up a cam for a 7200 peak, and guess what, it still peaks at 6300 because of the manifold. It'll carry the power out to 7200, but you don't gain much. The difference is, you lose a lot before 5k RPM because the cam is not designed for low RPMs. Also, every single LS1 has peak torque at 4800rpm. That's because of manifold design. Work with the manifold, not against it.

It's not rocket science to understand that if you run a FAST 90, you'll have to change the way you think. A custom intake with shorter runners will allow the cam to peak higher, but the FAST is a restriction that people refuse to acknowledge when they build these motors. Most of Futrals custom grinds actually have VEs that are near optimum for the FAST/LS6 style intakes, so like I said, Futral knows what he's doing, but if you look at the complete specs of the cams, they may seem huge at .050" but the way they are set up makes them effecient for the manifold restriction. A popular grind from Futral is a 246/250 112+4. The IVC on that is 51 at .050" which is perfect for a 408 with a FAST 90. Hence, the cam doesn't fight against the manifold, but makes tremendous power in the operating range the manifold allows for.

 

I just received a cam doctor on one of the big cams from Futral. It was lazy everywhere. That's not a bash. It's the truth. To run a super aggressive lobe on such at such a high duration on a hydraulic setup is asking for trouble. It's a great trade off to make power and acheive durability. But like I said, his packages are engineered to work in conjunction with one another.

Most other shops just throw a huge cam in with a very wide LSA and run low compression. But because it's a 408, it'll hit close to 500rwhp. When a properly engineered 408 would hit 550 for the same cost and just minor tweaks. But let's not go into all of that. This is about Tony's Vette.

 

Guys,

I built that engine with painstaking detail....from perfectly gapping the rings, to literally wet sanding some of the engine bearings to maintain all the clearances I wanted within .0002-.0003 (note the decimal place). I ported the oil galleys in the block, the pump, the intake manifold, and tried a few cams on the dyno utimately going with a medium sized street friendly solid roller set-up. Quench and other details of the actual build were also spot on, cam was of course degreed and the valvetrain geometry fussed with till it was perfect. This engine once again highlights AFR's successful approach to cylinder head design especially reflected by the RWTQ figures now over 480 ft/lbs with some additional time spent tuning. Thats a huge figure considering the moderate displacement and the fact the engine is only 11.0 to one (less than my 346 combo). I am very **** when it comes to engine building and the results usually reflect all the attention to detail spent. Considering my car put down 475+ RWHP on 5 different dyno's with my smaller cubed, smaller cammed stock 346, I think the numbers my 383 generates is very much inline, or should I say not hard to believe considering the extra displacement, lighter rotating assembly, added duration, and the perfect valve control and area under the curve a solid roller offers.

And the comment concerning Andy's dyno is total BS....The main reason he purchased the new dyno was to be able to do load testing (not just inertia sweeps), and while his former dyno read a bit on the conservative side, his new dyno simply reads more in line with any other calibrated DynoJet. A few people on this board have gotten a ride in my car with the 83' in it....trust me the numbers are legit.

Tony M.

PS....Wait till you see the next combo pan out (415 CID)...my hands were tied on some of the 383 parts and I didnt want to go to crazy with it so it better represented power from an "off the shelf" kit a non-supporting vendor offered. The new engine represents a clean sheet of paper for me and I'm really looking to maximize this build and have more freedom to do so....Hoping to have it finished in the next few months. Once again it will be a very powerful and very drivable N/A combination (not going to have a huge cam), much like the last two I have built but with more displacement and even more of the finer details touched on that will hopefully enhance power and reliability even more.

 

It's one thing to say that someone's wrong, but more worthwhile to the board to explain why you feel Jake is wrong. How about a detailed explanation? We'd love to be enlightened.

 

Are you going for 12's??








Can't wait!!

 

62 post Pat.. do you really think he has a detailed explanation....

 

I will be sure to let you cover the video chores Chris....especially the insightful audio commentary!!