M33P

Building a 408 for my 64 cutlass pro touring project. I've acquired all the parts for the short block so I am taking it the machine shop hopefully next weekend. This car is going to be a weekend cruiser and will not see track time. I want the power down low in the rpm band so I am looking at the tfs 225 heads and the cam motion stealthy stroker cam. I am however undecided on the intake choice as most I see are high rpm long runner manifolds and thats not where I want to make my power. Whats a good choice?

Last 1

iTrader: (2)

MSD or Fast I would say for a weekend cruiser

wannafbody

iTrader: (2)

Fast 102 with Cathedral heads, Rod Mod LS3 with rec ports.

AINT SKEERED

iTrader: (2)

408 will do better with msd than a fast

QwkTrip

iTrader: (23)

It's opposite of that. Short runners are for high RPM. Long runners are for lower RPM.

The runner length is a function of time it takes for a pressure wave to travel at the speed of sound through the length of the runner, and what RPM you want to optimize the volumetric efficiency (cylinder fill).

LS1 TJ

On my L92 swaps I used LS3 intakes. Worked well. On a LS2 sleeved and stroked to 427 cubes I used a LS3 intake. Bought the intake pretty reasonable off of Corvette Forums with fuel rails and injectors.
But with your 408 stroker I would be so tempted to run a short runner sheet metal intake for the only reason is that they look so cool. Your 408 depending on how it's cammed/geared should have a lot of low end torque no matter what intake you choose.

QwkTrip

iTrader: (23)

That is horrible advice. Yeah, let's spend many thousands of dollars on a stroker assembly and heads and then gut the torque curve with a Sniper intake.

QwkTrip

iTrader: (23)

Are those cathedral heads?

G Atsma

I see it way too often here where a sheet metal short passage intake is used "because they LOOK so cool!". NO street engine needs one of those!
That hood is closed more than open. And ALWAYS while driven.
And then the cam with "huge chop", not because they run so well on the street (they don't), but "because they SOUND so cool!".
ARE WE STILL IN HIGH SGHOOL?

LS1Formulation

iTrader: (13)

My Camaro has a NASTY idle, but tons of low end torque due to the ported rod mod intake. I'd never run a short runner manifold on the street. All in how you spec your combo. You can have your cake and eat it too.

LS1 TJ

I just said I'd be tempted. Never have run one.

grinder11

iTrader: (1)

I agree with this. I also say to each their own. BUT-MY own has never included flashy stuff under the hood. Reason being exactly what Gary pointed out. My hood stays closed 99% of the time. Plus, I don't like showing I have an LS7 in my C5!! Let 'em guess what just whooped their ***!!! If people enter a lot of car shows, I can better understand it. I understand the bling factor. One thing I wont do, however, is sacrifice performance for looks. I try to match components, and use what works best, rather than what looks best. YMMV......

M33P

Yes. I figured cathedral would be better for a street motor than the high flowing square ports. Also my pistons are 10cc dish so with the 65cc cathedrals it comes out exactly 11:1

slowride

iTrader: (3)

For stock intakes it would be ls6 (looks better) or tbss/nnbs truck intake for the best stock option. For the most power that keepsmost of the low end I'd pick a fast 102. I've seen the dual plenum manifolds work well if you have the space. What gears and stall do you have as that will make up for a lot of bottom end and when dealing with a 408 you should have plenty anyway.

5.7stroker

iTrader: (36)

Check out Richard holdener’s videos on youtube comparing intakes. Yes, what happens on a dyno isn’t what happens on the street, but it’s interesting data to look at. For NA performance, it seems like a stock LS3 vette intake on rec port heads and a stock LS6 intake on cathedral heads are hard to beat for cost/performance ratio. Peak HP starts falling off after 6500, which on a street setup, I’d think you’d want the power in the low-mid range vs upper range that short runner intakes offer. If you are trying to squeeze every last bit of hp you can on an LS NA street setup with cathedral port aftermarket heads and the goal is more power in the low-mid range, consider aftermarket options like MSD Atomic, Fast, and Pro Flow XT (needs cowl modified for fitment)

LS1 TJ

Just asking a question in regards to short runner lower cost? sheet metal intakes. Do the high end cost wise sheet metal intakes like Wilson or others lose the same low hp and torque?

LS1Formulation

iTrader: (13)

Runner length doesn't favor a brand. Short runners are for high RPM, period. Wilson could not design a short runner sheetmetal intake that could outperform an LS6 or LS3 under 5000 RPM. It's about the physics of airflow and that can't be changed, only designed around. Look at the TPI small blocks. They had really long intake runners and made gobs of torque, but the party was over by 5000 RPM. That's why so many companies made aftermarket intakes with shorter runners for them. And it's likely why GM went to a short runner for the LT1 - They couldn't meet their power goals with a TPI set up.

QwkTrip

iTrader: (23)

If you can fit a Fast LSxRT intake under the hood of that Cutlass.... ​​​​​​

M33P

The car has a tkx and ford 9" with 3.73s