Heads is the deal. My LT4 heads had 230 CC intake ports. One of the very sharpest cylinder head gentlemen I ever met did them. Pete Incado of CNC Cylinder Heads. Thinking he is retired now. His work consistently made the most power on my dyno back then.

The 7000 RPM limit with the fatory PCM was a problem for me. I fixed my own Opti issues, which was slinging the blade off the rotor after I went to the FAST XFI ECU, and started shifting it above 8K. Rotor did not like that. Had to put aluminium pop rivets in it. Then, finally had the main shaft bearing come apart. Went to an MSD crank trigger, still had the Opti there for the cap & rotor.

Made 537 rwhp, through an 8" non-lockup 4400 RPM converter. It liked shifted at 8400 with the FAST XFI. MSD coil. 4.30 gears & 30" tires. With open exhaust it went high 9.80s @ 137 MPH at Tulsa, not a fast track. If you ever been there, you know what I mean.

The much milder, NHRA Super Stock rules legal 350" LT1 in it now has gone 9.88 @ 134 MPH. 3250 lbs. Stock TB, stock valve sizes, stock port sizes, stock compression ratio. This one shifts at 8600, goes about that in the lights. Tick over 620 at the flywheel.

 

Thats pretty impressive, I would have thought it would take more than 537 RWHP to break into the 9's.. ..I'm guessing alot of weight reduction was also done?.. oh, just saw your weight at 3250 lbs, still pretty cool though.

 

This is very close to my goal, but I am slightly less ambitious lol.

Solid roller spec'd for 8k shift points on 24x setup, ~330cfm Craig Gallant ported AFRs, and a max ported supervic+4bbl TB. Want to try to run an offset and dropped air filter base to do an airpan setup and eliminate elbows and piping from the intake and get fresh air from the cowl. Starting with ~5200-5500 stall in a glide and 4.10s w 28" tire. Will play with stall and gearing after a few runs to see what it likes. Hoping to eventually squeek into a 9.9x at my admittedly faster sea level tracks.

Keep in mind 537 rwhp through an unlocked stalled auto is some pretty healthy HP. Also 3250 raceweight is NOT light at all, only around 100# lighter then my street car that still has radio w/ front speakers, stock carpet, stock front seats, power steering, etc. Without strict rules like Ed has to adhere to you can get close to 3k in these cars without going too insane, and make more power without having to keep stock valves, compression, ports, TB, etc.

 

Puck, you will want 4.30-4.56 gears and more stall (probably around 6000-6500) if you want to run optimal times N/A. My car is a dog N/A due to the nitrous converter (4500 tight stall N/A with 1600+ shift drops) , 3.7's and 28's. Also, my 3550 current race weight is not ideal. I still have some work to do on the tune but I think the combo only has a 10.7@126mph N/A in it as it sits. I took it to the track last week after working out some EMI/RFI issues with my FAST XFI and need to adjust the tune now that the ignition is fixed. It sounds like I have a glide in the car as I am in 3rd gear for such a short time.

Below is a video:
https://www.youtube.com/watch?v=z645...ature=youtu.be

 

I am having Tony Mamo do a set of AFR comp port 210’s and edelbrock LT4 intake right now. Shooting for close to 13:1 compression on e85 and 500whp thru a six speed.

 

AFR heads should make 500 RWHP with a manual trans a piece of cake.
I see guys using a single plane intake with the throttle body on an elbow, and wonder what they are thinking. I know it's more money for the cylinder head guys. I pissed away about three grand on different guy's manifolds, different elbows, and dyno time. Never could make what my old Hogan made. Since we don't race dynos, I also pissed away money on track rentals testing those intakes. Think I had one of everything Edelbrock makes.
If you had a low enough stall converter, it might leave a little harder. Best I saw from one of those things was + 15 ft lbs at 5000 to 5500. My converter flashes to 6400. From 6000 & up on the dyno, the Hogan sheet metal intake blew everything else away. My ported LT4 was second. I cut the top off in a mill so my cylinder head guy could fix the port entries, where most of the power & flow gains are found. Cut a new top from aluminum plate, and a friend tig welded it on. Last I heard it was still on my old 383". I heard from it's present owner recently, telling me "It's still a beast!" LOL
If you have a low enough stall speed converter, and foot brake your car, a single plane intake may be fine.

 

Hey Ed,
It really sucks doing R&D trying to go faster but it does gain you the knowledge and experience you have now. Do you still have that Hogan intake? What throttle body were you running on it? Did you spin the engine that the Hogan was on up to 8k rpms?

I am sure my intake is a little restrictive but I do drive my car to the track to race and back home (over 35 minutes each way) as well as to local car shows. I chose a single plane way back based on the plate system being better for optimization on a 250 shot (max I want to run) and ideal for the 150-200 hits. Did you ever do any testing on the 4bbl tb's?

pic for reference:

 

I do still have and run the Hogan on my 350" LT1.
On my 383", my welded & ported LT4 drive just fine on the street.
I don't care for spraying one. I much prefer doing it "all motor"
If I was trying to run in the eights, I might have to resort to that.
Or go turbo. I had a 58 mm TB on it.

The rules I run my 350" LT1 under now, none of that is allowed. I have to run an untouched factory TB, stock port sizes, stock valve sizes, factory chamber CCs, deck clearance & head gasket combination. I am allowed any valve trans & any intake, as long as the factory TB is in the original location. The sheet metal Hogan has been fastest for me.

I think you are mistaken about the single plane being better for nitrous. Makes no sense to me.
Not real sure why you don't think the Hogan would not drive as well on the street as a single plane intake?

 

Ed, You might have been reading into my post a little. I totally dig N/A setups that haul the mail like yours. Do you drive your setup on the street?
I am definitely not saying the ported LT4's, Hogan style, etc are not streetable. However, I do know the valve springs required to turn 8k+ rpms won't last too long cruising around town. I am sure 8's N/A with an LTX is doable now with all the technology available if you spend enough $$.

Those SS cars are amazing in the limitations put on the class and the ET's those cars can run and the 60ft's are crazy.

When spraying my old LT4 355" with a 250 shot on a single NX fogger, I could not get enough fuel to the rear plugs and it would melt the electrodes of off 7&8 cylinders before the 1/8th. I could spray 200 with no issues and 150 worked great (this was way back in 2003). I never fine tuned or dialed in any of the nitrous as I was very young and still learning back then (I literally put the jets in, made sure the pressure was good and let it rip). When I did my research way back, the single plane and plate were the best way to get a 250 shot to distribute to all cylinders as compared to an LTx style with a forward mount tb and single fogger (without going dp of course).

The setup I run is more restrictive than an open 4bbl tb as I am running a 3.5" tube with a carb hat that runs to a K&N in the stock location.

 

Mat, if you knew how to tune your FAST XFI in Sequential Mode, you could have tapped a couple of keys, and put enough fuel in those back cylinders. If you dynoed it with 8 wide band O2s, you would also see that #1 & #2 cylinders are a leaner as well.

Not sure about your valve spring therory? Sounds like you also don't use PAC valve springs? If you have a solid roller, look into 1356 PACs. I run them two seasons. On my old 383" (not over .800" lift like I use now.) they lasted about forever. The 1356 springs are only 1.5" diameter. They clear everything. Too strong for a hydraulic roller, but not many would want to spin one of those things over 8K anyway. LOL

 

Ed, the old 355 combo had the stock pcm and opti way back when. I am running sequential mode on the FAST XFI and am still learning how to tune. I am getting some assistance from Brian Macy on setting things up correctly and it has been a great learning experience. I do know how to retard individual timing and add the offset for fueling on the FAST XFI. I do know now that you can do that with the stock pcm to a point as well but I did not tune the old combo (Joe O did the dyno tune on the old 355 combo).

Good point on the #1 and #2 cylinders being lean as well but on the old LT4 intake with the stock PCM the back ones were way leaner than any others.

I don't have the capability to run 8 widebands at this point so I will result to old school plug reading to get the balance corrected. Do you have any experience with which cylinders run hotter with a single plane? I am finding that #4 and #6 look the leanest with #8 looking the richest so far.

I believe the springs I am running now are made by PAC (Comp 943's).

BTW, what are your thoughts on what ignition timing on stroker ltx's and sbc's? I am still trying to dial in the correct timing the engine likes but I find only small gains (.2 mph in the quarter) with adding 2 degrees of timing.

Also, what A/F ratio have you found works well for these combos? I am running 12.6 A/F but did try 12.8 but it made no difference in ET/mph so it seems the optimal range of A/F is not as precise for max power and that similar power can be had with ranges from 12.4-13.1. (I am running Sunoco standard 110 octane while tuning).

Thanks for any info,
Matt

 

If you know how to read air/fuel on the plugs, you know you have to put in neutral& shut the engine off at the finish line. Just coast to a turn off, and either let the headers cool some, then pull the plugs there on the return road. Either that, or have somebody tow you back to the pits.
I don't know what fuel you use (they don't all like the same air/fuel ratio, and all wide band O2s give the same numbers. In a perfect world they would. Out here in the real world, they do not. Leaded fuel is hard on them anyway. Get your car dialed in dead nuts, plug another/new O2 sensor in, and your numbers likely all go richer or leaner. I was able to find two that give the same numbers. I keep one for a spare. I have found them to give leaner data as they deteriorate. If mine starts to look leaner, I check the fuel pressure. If still OK, I try the other sensor. Usually the culprit. Then I buy another new one. I plug it in for a couple of passes. Then label it plus .2, -.2, or what ever.
You need to know where it's fastest on a given sensor. Usually (always in my experience) it should be richest at the torque peak. No dyno time, you don't know where that is. Mine runs the best MPH a little leaner than that. Leanest right in the 1/4 mile lights. 12.88-1 at torque peak, to 13.2-1 in the lights.
Your results may vary. I use VP C11 fuel, and 38 to 35 degrees, depending elevation & conditions.

 

Thanks for the info Ed! I did not know about wb variability (another moving part!). I am running 36-37 degrees WOT throughout the quarter so I feel close. Still trying to dial in the A/F but I think I am close as well (thanks for sharing your experience). I appreciate your reply.
Take Care,
Matt