I'm looking for the lowest profile intake/filter and am curious about the Spectre low profile setup. I've got an 82 with a 427 sbc with about 625hp. I need flow! I think I need over 1,000cfm and I have limited clearance. Currently I have a 14' cleaner with a 2.3" filter and it's just not enough but I have no more space. Anyone have pics or comments on the Spectre unit? I do have an aftermarket twin turbo hood which gives me a 3 inch cowl and I don't want to cut into it.
Thanks all!

 

I assume you are not interested in a drop-base air cleaner.

Depending on what carb you have, your 2.3" element is getting too close to any fuel bowl vents. For example, Holley recommends a minimum clearance between the vent and the underside of the air filter lid of 3/4". Here is where an aftermarket air cleaner benefits. The lids are usually "domed" to gain clearance.

Car part stores are of little help finding custom size air filters. Without a VIN they can't look up anything. The VIN is of no help for us with our modified SBC.
I have done numerous searches on Google for a 14 X 2.75. There are tons of them. Conical shaped, rectangular and square. No round, old school ones.

 

The Low Profile Drop Bases are primarily designed for Holley Carburetors and I have not seen one for anything but a Holley. I have a 1968 L88 "replica" and the L88 drop Base is a great one for cars needing hood clearance. Today I have it on a Holley Stealth Sniper EFI system and it is keyed like the Holley carburetors so it works just fine. The air filter lids made by K&N (X-Stream top filters) for air filters are a great way to keep them open for as much air as you can get into the carburetor. With the limitations of a 2.3" tall filter it would be tough to pull 1000 cfm through it. Using a L88 style hood with air box the engine is able to get all the cool air it needs. My BB 427 gets to breath all it wants and or needs even with an Edlebrock RPM Air gap intake on the engine. The only negative is that I don't have any type of air filter other than a K&N Wrap around the big screen in the hood.

The colder the intake/Combustion air the more power the engine will make. That is one reason the L88 hood works so well as the intake air is virtually the ambient air temperatures and this keeps the high compression from detonating without any other tricks.

 

I think I have the solution and it's the X-Stream. I just got off the phone with K&N. I have a K&N E3740 filter that is 2.3" tall and flows 610cfm. They said that my engine setup needs a min of 865cfm to take advantage of the RMP range to 7,000. 692cfm min for daily driving but who wants to do that, ha! They actually did a test on the E3740 and compared the flow when adding the X-Stream filter top and it went from 610cfm to 1040cfm which should do the trick. I don't have the hood clearance exactly but I should be good to go! Got the K&N S-Stream 66-1401,

I do have the twin turbo hood so I do get a little extra clearance and hopefully some of the fresh air flows in through the vents.

 

My 427 has a hunger for air and over 1100 cfm of it when turning close to 7k rpm. I have a AED carburetor that flows over 1100 cfm and is based on a 850 Holley Double Pumper. They built it custom for my engine when I was playing with engine designs. My little 427 was balanced at 7k rpm but it drops off like a cliff at the high 5800 rpm range. I have taken it to close to 7 k without any issues but now that the engine is over 20 years old I am hesitant to trust the valve springs as I had only .125" of clearance when new between the pistons and the heads. A floating valve could ruin my hole day. The EFI system I have has been working great so far but the throttle body is only rated for 900 cfm if I am not mistaken. My engine was dynoed at 582 hp when it was new and with my 3.36 rear it allows me to get sub 4 second 0-60 mph times and 11 second quarter miles. The problem is there is little traction on the stock size tires and this is the next major project. I want to switch to some 18-20" rims and tires so I can find a stickier tire. At the 1/4 mile I spin my tires past the 1/8th mile mark, it sounds great but limits the times I can turn without a roll cage. The car is totally undriveable in the rain or on any wet roads as the *** end swings all over the place. I have raced 2 stock 1970 LT-1's and a 1969 L89 all with 4.11 rears and I beat each one very soundly. I like my 3.36 rear even though the folks at Comp Cams told me I HAD to switch it to a minimum of 3.70 or else the car would be a dog... Boy where they wrong.

There is nothing like the torque of a 12.25-1 Compression ratio BB 427, it squeals the tires when you get on the gas and chirps them when you let off the gas. It attracts way too much attention from the local LEO's of whom most of know the Car and know that it is very capable. My engine builder built an old AC Cobra a new 428 Ford engine and my Corvette tore than car up in the straights and especially in the turns. I love the power but it is just a bit too much for a daily driver. I have always wondered how a SB 427 would compare to a BB 427 engine. Had budget not been an issue I would love to have an all aluminum BB 427 like the ZL1 Corvettes had.

When I saw your post I immediately thought of the K&N X-stream air filter lids as that is an awesome way to get the right amount of air into your engine, especially with a tight engine compartment. I wish they made a 5" one for the carburetor top above the small screen. I have a big screen in the top of the hood in the airbox with the K&N Filter Wrap on it to keep the bugs out of my engine. I also have a Water/Methanol Injection system to keep my engine happy during warmer weather. It gives me the equivalent of 115 octane and the water cools down the flame inside the combustion chamber. With cool air going into the engine I can drive on 93 octane Sunoco fuel in the cooler months but need the water/methanol when the engine gets really hot in warmer weather. My biggest concerns are about engine heat so I have spent a lot of time trying out different cooling methods. My engine currently has Evans NPG coolant in the system which is a totally water-less coolant which really helps prevent detonation even more by removing the heat better from the engine. On most street driven cars I recommend that people use the Red Line Water Wetter to help the engine stay a bit cooler, you might need it as well. I have a Be-cool Radiator with 2 SPAL Fans in a shroud on my Corvette and that struggles to keep it cool in heavy traffic.

 

To achieve 625 hp takes a tall single plane. Which is what I have had with a 1/2 inch 4 hole wood spacer for the past 15 years with my T T hood.

 

You have to use intake manifolds that match your heads intake port size. What heads do you have?

I use a K&N dropped base air cleaner 2 X 14 with air top filter

 

I use a really tall Motown single plane and a 1/2 inch 4 hole wood spacer. The angle that your motor installed matters. The front edge of the air cleaner is the closest point to the TT hood because the slope. I made a custom aluminum block spacer to raise the tranny tail shaft, which lowers the front edge of the air cleaner. I use a 830 cfm carb and it powers into my 7500 rpm rev limiter. My max HP is at 6800 rpm



Just taken today

 

As my power went up so did my tire size. 335 width on 13 inch wide wheels. We have been having pouring down Monsoon rains lately. I find it to be fun driving in the pouring down rain. My tires have enough bite to get wheel hop on a WOT launch. It actually really takes off without spin if you do it right.

 

I'm estimating 600-630hp. I put my specs out on a hotrod forum and 625 plus or minus was the general consensus. And compared it to some other builds that were dyno'd. Specs:

Dart SHP SBC block- 427ci stroker

Fully forged bottom end with Callies crank, Compstar H Beam rods and JE forged pistons

Brodix Track1 Aluminum heads- CNC machined, blended valve bowls, 3 angle competition valve job, 64cc/215cc . Part 1008103

Brodix HV 1000 port matched single plane intake- 6.225 height, 4,000-8,000 range

Comp Cam custom grind roller

*Duration @.5 256/266

*Lobe Lift .423 intake .426 exhaust

*Lobe Separation 111.5

*Valve adjustment .026/.020

*Gross Lift .676/.681

*Duration at .20 tappet lift 287/298

Comp Cams 871-16 Endure-X solid roller lifters

Comp Cams Ultra Pro Magnum 1.6 rocker arms, 7/16 stud. Part 1605-16 with stud girldes
Holley Sniper EFI X-FLow 550-545- Good 800 plus HP.

Tremec T-56 Magnum trans

 

We have similar motors. Valve stem lash caps are a good item. I also run. 012/.014 lash. Easier on parts

 

I'd love to see a pic of your car if you have one handy. Did you do anything to your differential to handle the power? I'm using a rebuilt Dana 44. Supposedly built to handle a little more power but still one of my weakest links. I'll probably do the iron conversion and go with 4.11 gears. All it take is money, ha!

 

I have Tom's rearends with bigger everything and 4.11 gears

 

I used to break posi cases about annually, yokes went away, u-joints failed, and outers would twist. Big slicks are hard on stuff. I just have a TKO 600 and I have tried different flywheel weights and 22 pound 168 tooth 11 inch ACT 700 ft pound manual clutch is excellent setup.

275/17 fronts with 335/17 rears. Big GT1 Wilwood road racing brakes. As I went faster with bigger motors the stock brakes with 600 degree fluid would completely fail in just a couple of laps with boiling.



The view most people see! Actually 345 width road racing slicks. 3 inch exhaust with H pipe into 3 1/2 in and 4 inch out race mufflers with 4 inch diameter chrome tips

 

My engine was built by a well known very experienced Porsche Can Am racing engine builder here in Northern Virginia and it all started with the 4 bolt main 427 engine big block. The compression is very real and from everything I have read there are not many BIG blocks that really "like" spinning above 6k. The engine is a locomotive that makes incredible torque at low speeds. The car has a 3.36 rear and even with that it will take a 1970 LT1 with a 4.11 rear down in the 1/4 miles easily. The same for a factory stock 4 speed 1969 L89 with tri-power and a 4.11 rear. Everything inside my engine is forged and made for making power even with high compression.

I have a Gtech Pro and it's shift lights indicates the torque dropping off around 5800 rpm but the engine will continue spinning up to close to 7k if you ask it to. My transmission is the standard Muncie for 1968 and even with the four speed at the race track I spin my tires past the 1/8th mile mark. Once I tried my buddies D.O.T. street slicks and I promptly exploded a half shaft joint at a moderate take off. Having the stock rear is a limitation for my car which means for the best times I have to take off slowly and let the engine go to work without shredding the tires. I would certainly break something if I used those slicks you showed in the picture.

Whenever it rains the "plain Jane" BF Goodrich 255/60-15 tires just fishtail the rear all over the place. I used to take the car when I went flying and would make a few runs on the runway before it woke up in the mornings. The Gtech says it is doing low 11's in the quarter and it pulls very hard from 30 to 100 mph. I would easily get to 120-125 and then have tons of room to slow down on a 2800' runway. The only thing about going fast with a 1968 is that the front end starts to lift above 115-120 mph even with a cast iron engine in it. The lift is reduced when I have the 1978 Pace car spoiler on the Corvette.

According to a Corvette Big Block expert (Hib Halverson) I am not using the right camshaft to get the most out of this engine. Comp Cams was not happy when I told them about the 3.36 rear as they insisted I needed a 3.70 or 4.11 minimum with this engine. Basically the cam specs are the same as the L88's were built to. My pistons are from a L88 engine and the compression is very real, 12.25-1 is what the numbers came out too when the engine was built. When I do a Compression test I see roughly 250 psi per cylinder and I use both a Gear drive starter and Pull the timing during cranking. The engine ran it's very best with the AED carburetor on it on the road but now it has a Holley Stealth Sniper EFI system that I am still dialing in. The car has a 3" exhaust Chambered Exhaust system and sounds like it is spitting out the rear of the tailpipes. I get so tired of the Asian cars that all want to race my old Corvette, I just smile and laugh them off as I drive away. I don't live in an area where you can drive very fast and many of the local LEO's all "know" my car and where it lives. I would love to do a "flying mile" at some point but only after I switch to some tires that stick and can handle the speeds safely. A buddy of mine had a 1964 GTO with a 389 and the three deuces along with a four speed and he was scared of my car after a short ride on the interstate.

I have been very curious what a small block 427 feels like in comparison to a BB 427 does. I built a 327 decades ago and I really loved the way that motor revved. The 427 revs so much differently than the 454's do, the difference in stroke makes a big difference in my opinion. I did like driving the 1970 LT1's however, they sure had a great spinning engine. On 7 cylinders I was able to outrun Ford Mustang GT 5.0's of the late 1980's. When we built this 427 the BB parts were very expensive and I saw it as a challenge to make as much power as we could with this 427 so I went with the L88 design and have never regretted it. The engine builder and many others tried talking me out of building an engine with the compression. It allows me to go 0-60 is the mid to high 3 second range and there are few cars out there who can do that. It is the only vehicle that "scares me" and I have driven some really fast/radical vehicles over the decades.

 

love these threads...:-)
i turn ~530hp and ~560tq at the rear wheels... so i should be at 650HP at the crank////...
my cam is much smaller??

​​​​​​My 427 build from the bottom up:
Dart SHP block
Milodon 7qt road race oil pan
Milodon diamond stripper windage tray
Calis Dragon Slayer Crank
Skat H-beam's
Probe racing pistons 11.3:1 forged
AFR competition ported 220 heads w/titanium keepers and locks
AFR plastic single plain titan intake manifold
sportsman FAST EFI 2.0 fuel injection system.. 1200cfm
MSD full ignition with crank trigger
Kooks 1 7/8 ceramic headers
3" duel mandrel bend exhaust with X-pipe custom made by D&C design... my son Danny:-)
Borla mufflers
march pulley system
22 lb steel billet flywheel
McCloud twin disk clutch
Fluidamper 6 1/4" HB
Custom Cold Air Intake by me:-) D&C design
Custom cam by Strub 611/592 244/248 109 Sep
Morel reto hydraulic lifters
Crain gold race RR's
TKO 600 transmission
SUPER 10 rear end built by trackdog2
18" custom built 2 piece centerline wheels
Willwood big brake system all around
hydroboost braking
rac-n-pinion steering
550 springs up front, 360 composite in back with all Bilstin sport shocks and front and rear sway bars
3" HD Dewitts radiator
DELTA PAG brushless fan w/D&C custom fan shroud
Dewitts 3" heavy duty radiator

 

I'm surprised that I would be at or near the same hp, with such a smaller cam???

 

It's all about head flow. more flow from intake, heads, and exhaust require less cam.

 

horse power does,,,, torque comes from CI and compression...
I did not see the op's heads, or CR...

that's probably the reason for the low hp with that cam...

I start making power (400 tq) at 2,000 rpm I believe. wind out at 7k rpm...

 

The op's heads are listed. Compression is 11.5:1

Im estimating horsepower. Curious what others think it might be.