I wish there were more interests in alternative intake manifolds in both the LTx and B-Body Community. We could definetly use a much longer intake runner to get more low and midrange torque out of motors. Sorry 3" from plenum to intake port is NOT the way to go to produce decent torque numbers. I think the LT1 produces a nice flat torque curve and good torque numbers inspite of itself and its intake not because of it.

So in your opinion what is the best and cost effective intake on the aftermarket, short of fabbing up a sheetmetal intake to put on a LTx motor for a high performance street Impala SS/Caprice??
Stealthram?

GMPP Ram Jet 350 intake manifold??

A converted single plane carb intake???

Or even Edelbrock's new Pro-Flo XT??

In my research people on the forums mentioned something about "cutting and welding" the stock LT1 intake but they did explained what that meant. Can you please enlighten me of what that entails and is it worth the effort???

 

Basically by cutting and machining the intake runners down your shortening the rpm band.Its the reverse of porting a stock tpi to move the power band up and gain more horsepower..by making it shorter your will produce more torque and lose top end horsepower.Also note that the torque curve wont be so flat anymore..its will peak and then fall off very much to the ported tpi setups out there and you will limit the peak rpm range aswell.

If anyone has a better way to explain it or add anything else please do.Im pretty sure thats the just of it anyway.

My question is why do you want to limit yourself to such a torquey lt1 motor?they are known to be still a very potent engine with great torque after heads cam and exhaust work and still pull great uptop past 6000 rpm...unless you just want a torque monster tire shredding..light tolight motor then find yourself 350tpi and do a good head cam and intake port and exhaust setup.You will have more torque to scare alot of ppl on the street.

 

Lingenfelter made an LT1 SuperRam back in the day. On the stock automatic cars it would drop ETs around .3 seconds. However, it never really caught on because it was expensive and people could go just as fast or faster with the stock LT intake spending the same money on heads and a cam. However, if you're wanting an intake to boost midrange torque,, it would do that. It might not be easy to find right away,,, but I've seen them pop up on forums and e-Bay every now and again.

 

I am familiar with the Super Ram. like you siad way too much money for the perfomance increase and a PITA to install and work around.

Are they guys out there who have used the Holley (now Weiand) Stealthram on a LTx motor??

I know you Third Gen guys don't have as bad the hood clearence issues like the Fourth Gen. people have. And I know it has no problems clearing a B-Body hood. Iseen it done.

 

Nothing is really wrong with the LT1 intake. I owned an Lt1 for a couple years and never worried about it's flow. 13 flat with some bolt ons and stock 3.23s. With your B-body, you should look into gearing and a cam that boosts low-mid range to get that beast rolling. Besides, the fastest LT1 is within a tenth or two of the fastest LS1. Proper gearing, stall, tune and a higher powerband because of the shorter runners will more than make up for the "loss of torque" you feel.

As for your question on porting and LT1 intake, the gains are minimal at best. Edelbrock sells an LT4 style intake, but it's expensive and the gains are negligible because you need the proper heads to go along with it.

Go visit Camaroz28.com, it's more for the LT1 crowd.

 

Exactly BigWhiteGTP, the correct combination of parts far outweighs any kind of porting that could ever be done. Never been a big fan of porting anything, myself.

 

Listen I know that there is nothing wrong with the LT1 intake it that there is nothing all that right other than its ability to breath at high RPM's (6000+).

It is fact that the main design consideration for it other than the high RPM breathing ability (which we all know that the TPI sucked or I should say didn't suck enough at) was to clear the hood of the 4th Gen F-Body. If short intake runners were such a great idea why didn't GM continued it with LS1????

BTW I do have 3.73's in my 9C1 and I am on this forum because it seems the you Third Gen guys seem to have more out of the box thinkers and not go along with the party line comrade.

Hey isn't this forum is labeled "Alternative Port EFI Intakes" !!
I thought that mean't something.

 

They still use a fairly short runner at around 6-7" which boosts torque in the midrange and yet still allows it to breath very well into the 6000+ rpm range. Guys that go to single planes that possibly have shorter runners are building motors for higher rpms and do make more power. You shift your power curve up with short runners so you have to shift your stall speed and gearing up to get the car in that power band else its a SLUG at lower rpms.

My stock L98 with 2.77 gears would light tires up with stock converter and good 245street tires. My stock LS1 99 trans am with auto/2.73 gears can be full brake torque launched on the street on its 275 tires. Sometimes doesnt even chirp. The torque output of the L98 is greater off idle than the LS1 due to the runner length, even tho the ls1 makes more power overall. LS1 will want 3.23-3.42 gears to better match the power band.

For your heavier B-body, if you stick with the LT1 short runner intake which does make good power and STILL can make good torque regardless of the runner length, then you'll want to consider more gear out back and higher stall torque converter to better get it moving. You have 3.73's and if you run something like a standard 26" street tire you should be ok. If not and you run larger diameter wheels/tires, it may want 4.10/4.11's depending on motor power band and tire diameter. 3.73's should work well tho.
There is a LT1 vette guy with LPE 219 cam and AFR 195 heads making 422whp and 380wtq on stock bottom end 350 LT1. My big 383 Stealth ram thru the auto made 400/380 with much bigger cam and same AFR 195 heads just the sbc version. Granted different dynos different air conditions and he may have had a 6 speed I cant recall so the numbers are abit off from apples to oranges but does give idea that LT1's can make good torque. Get great flowing heads, keep the cam on the smaller side but with good lift and it will make torque with hp to back it up

A good intake for you however would be a converted HSR (holley stealth ram if you dont know the popular abbreviation HSR). Company over at LS1 tech and possibly on corvetteforum was advertising the converted LT1 HSR to fit under stock Fbody hoods so it may clear b-body as well. THey posted good gains over the factory LT1 manifold on both mild motors and abit more aggressive setups i believe.

HSR flows more than most ported LT1's. If you wanted higher flow you need to cut and weld the runners up on the LT1 to get more flow due to larger runner volume/etc. Miniram intakes are like the LT1 but feature larger runner area and flow more. There are guys porting and welding those minirams to over 400cfm!! That will out flow any head you will run on a 23 degree motor. 400 aint the norm but 300cfm is easily achievable and good match for most 23 degree heads.


Converted single plane may be a good choice too since they will have longer runners than LT1. Torque output will be good like the HSR, but response may be better and air distribution may be better. HSR is known to have air distribution problems between front and rear cylinders. I believe its a part throttle/idle issue and its ok at WOT but i could be wrong.
Alot of guys here that have converted to the single planes do love them and say throttle response is crisp and power delivery is strong at all rpms. So it would be a good choice as well, just have to run either a MPFI carb-type throttle body and air cleaner, or buy a intake elbow and run LS1 TB which will wire into your existing TPS/IAC sensors wiring I believe. IF not just get LS1 connector pigtails and wire them in. Color of the wires match the stock wiring, or atleast it should. It does on my 89 camaro so its the same between LS1 years and 86 up GM TPI cars. I think LT1's are the same as well.

Does this help at all?

 

Orr89RocZ, Thank you for very informative reply. I was wondering if the HSR might be the answer but there seems to be alot single plane carb intakes more than the HSR's floating out there.

I wasn't looking for a low RPM stump puller/tow vehicle with 12" runners, but 6" to 8" is way better than 3".

Again Thanx!