TPI VS TBI on a performance intake

[Supercharged111]

For me it was the opposite. Black box liked timing and no knock counts to speak of. 0411 had places it was pulling 10° retard with the stock timing table. Remember the Vortec heads flow better than the aluminum heads. Post the dyno sheet of your F-car. I can post one of the 395 cam in a L31 with a marine intake. LT1 cam has a broader power curve than the L31 marine cam by far. Granted I had tri-y headers and was pushing power through a 4L85E/9.5" 14-bolt while turning a mechanical engine fan. Your LT1 murdered my L31 marine setup. Was not until I put E85 in it that I was able to get some timing in the lower rpm ranges. I made 230 hp and 304 tq with the marine cam and weak valve springs. 257 hp and 310 tq after swapping the springs. E85 pushed it to 272 hp and 330 tq. On E85 it liked 32° total advance from 2,400+, no less, no more. 2° either way anywhere in the curve killed 10-15 ft/lbs. On 91 it detonated at anything more than 24° below 3,200 and I had to limit to 29° total with advance peaking at 4,800.

It figures I can't find a copy of the Dyno right now. It laid down 292/329 IIRC with a horizontal line for a torque curve. Now that I'm thinking back, I think the best I ever saw was right around 330wtq with a truck cammed LT1 aluminum headed car motor. Back then the car ran a 36mm restrictor. As of now, having improved crankcase ventilation, I'm down to a 35mm plate so definitely right around the 300whp mark uncorked. 1mm is right about 7whp. This is untuned with stock exhaust manifolds, a T56, and 7.5" rear end. I'd need to look again, and it's not apples to apples because of my elevation, but I swear my truck takes more timing than your van. At least before the blower.

 

[L31MaxExpress]

The old LG4/LE9 305s used to be the same way. Stock cams were so small that they would crank at 195 psi. Had to limit total advance to 26° and 4° initial with the stock cam. Chunk a 204/214, .423/.446 lift RV cam into them, give it 12° initial and 34° total and it woke up everywhere. Stock head could not get any airflow trhough a 1.84 valve with only .390 lift. Put a 218/218, .450 lift cam in it with a 2,500ish stall. Initial advance at 16° with the centrifical limited to 36° total at 2,800 and it would fly. First cam dropped nearly a full second off the 0-60 in my G20. 2nd cam and stall dropped another second off it. All three cams tested with a performer rpm spreadbore, tweaked q-jet and thorley tri-ys into factory true dual 2.5" exhaust with an added x-pipe.

 

[Supercharged111]

The old LG4/LE9 305s used to be the same way. Stock cams were so small that they would crank at 195 psi. Had to limit total advance to 26° and 4° initial with the stock cam. Chunk a 204/214, .423/.446 lift RV cam into them, give it 12° initial and 34° total and it woke up everywhere. Stock head could not get any airflow trhough a 1.84 valve with only .390 lift. Put a 218/218, .450 lift cam in it with a 2,500ish stall. Initial advance at 16° with the centrifical limited to 36° total at 2,800 and it would fly. First cam dropped nearly a full second off the 0-60 in my G20. 2nd cam and stall dropped another second off it. All three cams tested with a performer rpm spreadbore, tweaked q-jet and thorley tri-ys into factory true dual 2.5" exhaust with an added x-pipe.

I had a 204/214 in a 289. Carb'd it kinda needed to come on cam but once I slapped an Explorer intake on it with 5.0 HO computer it was vastly improved. Case in point, the intake dictates torque production far more than the cam does. Carb'd I'd tuned it with a wideband and recurved the distributor to bring total timing in by 2500. That woke it up big-time, and EFI woke it up even more.

 

[L31MaxExpress]

It figures I can't find a copy of the Dyno right now. It laid down 292/329 IIRC with a horizontal line for a torque curve. Now that I'm thinking back, I think the best I ever saw was right around 330wtq with a truck cammed LT1 aluminum headed car motor. Back then the car ran a 36mm restrictor. As of now, having improved crankcase ventilation, I'm down to a 35mm plate so definitely right around the 300whp mark uncorked. 1mm is right about 7whp. This is untuned with stock exhaust manifolds, a T56, and 7.5" rear end. I'd need to look again, and it's not apples to apples because of my elevation, but I swear my truck takes more timing than your van. At least before the blower.

As luck would have it after almost 5 years the only one I can find is the weak valve spring pull. It was about 90°F in the shop and the clutch fan engaged halfway through the last pull. Boneheads also tried a 3rd gear pull and hit the speed limiter I had set to 100 mph to keep the driveshaft in the thing should they try a 3rd gear pull. They also insisted on pulling it in drive even though I told them to just use 2nd. 2nd gear start was active. They could have pulled it from 1,000 rpm to redline in 2nd with the converter locked had they just listened to me.

Part of the waviness is from the fan clutch partially engaging in waves. They let it idle for too long before trying to pull it.

You must be registered for see images attach

 

[Supercharged111]

As luck would have it after almost 5 years the only one I can find is the weak valve spring pull. It was about 90°F in the shop and the clutch fan engaged halfway through the last pull. Boneheads also tried a 3rd gear pull and hit the speed limiter I had set to 100 mph to keep the driveshaft in the thing should they try a 3rd gear pull. They also insisted on pulling it in drive even though I told them to just use 2nd. 2nd gear start was active. They could have pulled it from 1,000 rpm to redline in 2nd with the converter locked had they just listened to me.

You must be registered for see images attach

Gotta love the shop guys that know more than you, right?

 

[L31MaxExpress]

Gotta love the shop guys that know more than you, right?

Especially since I had taken the time to flash the PCM with 2nd gear start used as a dyno mode and forced the TCC lockup in 2nd at 25 mph.

 

[L31MaxExpress]

This is a comparison between the results of a factory Ramjet crate engine vs a Ramjet with a LT4 Hotcam. Same 1.6 rockers too. Just swapped the cam, retainers for 787s and 918 springs. LT4 Hotcam was advanced 4° to a 105° ICL. With a 2,400 stall a person would never feel any loss at WOT. Hotcam might be a little weaker at low-rpm part-throttle but more power is just a short push of the pedal away.

You must be registered for see images attach

 

[racprops]

I am reusing the original bolts as this is near stock motor.

I only see a possible issue or three. I am concerned with the 9.5:1 compression with a cam and engine that size having detonation due to very high cylinder pressure. The Rhoads lifters will increase this tendency. This combo will likely not want much ignition advance. I am also concerned that the Valvetrain noise will tickle the knock sensors. I don't know if the Fast system uses knock sensors. If you see knock at hot idle from valvetrain noise you may be able to dampen their sensitivity. The "D" dish and small chamber will mitigate that issue somewhat. I would run the FST-302000-06 computer/harness from Summit Racing. It is a self tuning (mostly) computer and you don't even need a mass air flow sensor. That computer does not understand boost just so you know. A set of Rhoads lifters shouldn't give a second torque peak. It is much more likely have a wider flatter torque peak.
I have used Rhoads lifters for over 35 years nd they work as advertised.
I also will not build an engine without Total Seal rings. In my opinion building an engine without them is a waste of time and money. My Firebird engine has KB pistons, Total Seal street rings (The gapless top rings didn't exist yet when I built my engine or I would have used them) and a compression ratio of 9.14:1. You cannot turn the engine over by hand because it will push the wrench back where you started when you try to ratchet it back!
+1 on the head bolt sealer on the bolts. All 17 head bolts on a small block Chevy go into water.
The ARP-100-9904 thread sealer is $10.99 as of today at Summit Racing
https://www.summitracing.com/parts/arp-100-9904

You WILL have coolant in the oil if the bolts aren't sealed.
There are mistakes on the Summit website. What is the part number for the bolts you purchased?

 

[racprops]

Well I see again everyone is thinking like a normal hot rodder, all about HP and RPMs...

The cam profile I wanted for my base came out of a 350 from a 90s Cadillac, it was a factory set up.

The cam profile I will have once the Rhoads lifters pump up will be close to a article on building a Torque centered low RPM (max 4800RPMs) 383.

And yes I have read that I should see a more flat power curve...

Here is two pictures one for the Caddy cam and the other of a TPI tests ran on a stock 90 Camaro 350 testing the TPI with various add ons.

And again the TPI Testing was with a stock 90 cam which like all cams for a street car torque peaked at 2800/3000, so I have NOT found any test with a stock Caddy, or vam cam where the torque peak of 2200RPMs.

You must be registered for see images attach

You must be registered for see images attach