Well i went to a different shop to confirm my afr was correct so i wouldnt have to spend 220$ for a wideband gauge as it was 75$ for two pulls with wideband o2 on the dynojet 248. These numbers look to be correct compared to the dynocom 5000 dyno numbers.

It made 349whp/351wtq 12.5afr-13 tops 99 corvette stock auto 3.15 gears with elgin 1839 220/224 .575 cam, tsp headers, stock 2.5" exhaust, better mufflers and volant oval filter. I think an ud pulley, ls6 intake and 243 heads would get it close to 400whp maybe. My 6 speed 98 z28 with 3.42 similar but smaller cam hooker headers free flowing exhaust and ud pulley stock 98 intake had made 375/375 on mustang dyno. It was worth the 75$ to confirm afr from a second shop and better dyno graph not sure what other upgrades there are if a varam power duct adds anything someone told me they lost 2-3hp. Maybe a 3.42 gear change, ud pulley, ls6 intake, 243 heads is only thing i can think of.

 

look right to me for an auto ls1 with a small cam

 

Looks about right to me.

Friend w/98 WS6 M6, LS1 intake, T1 cam 221/221, mid length headers made ~361 whp

I don't think you'll hit 400 whp with a stock LS6 intake & stock 243 heads. More likely ~380 whp with that small cam. Definitely think with a good set of ported 243 heads you'll break 400+ whp with an LS6 intake.

Good luck either way.

 

yeah does anyone know if an ls6 intake does actually add 10hp over the stock ls1 intake or is it more like 5 hp? ASP claims just over 13hp on a stock ls1 with their underdrive pulley so i think it can be done. That would be about 20 hp in an ud pulley and ls6 intake making it 370 roughly. Be lucky to get 243s to get 30hp out of it may be possible. The 345 base-405 z06 was from the 243 heads, 10.5 compression, ls6 intake and the .550 lift cam so its hard to say how much hp was added to each when add to the base 345hp ls1 engine. Yes if i had enough id sent some 243s in for katechs 500$ porting with stock valves but im on a budget if i ever get funds. Was just trying to confirm tune afr was correct it was cheaper to pay 75$ here two pulls wideband afr log 12.5 vs paying 200$ on a wideband. From the dyno below hard to say if a ud pulley does for sure atleast add 10-13 wheel horsepower would get 360whp and advertises 2-3mpg gain not sure asp claims. Its not too small not too big 286/282 220/224 112lsa .575 lift can always add 1.8 rockers to get .607 lift but not sure if any power is in there. Really needs atleast 3.42 gear or 3.73s 3.90s. I find myself once i get out of first being auto missing the 2-3 6 speed ratio gearing with 3.42s and a long 2nd gear till 3rd or drive 1-1.

My 98 z28 6 speed 3.42s with a slightly bit smaller cam around same .580 lift i was told and hooker headers 25% ud pulley made 375/375. Im trying to get somewhere around there i think the 243s would get it around there or 365 with ud pulley ls6 intake. They dont have the air bridge if it is restrictive and have a groove to port the throttle body. I a couple tuners told me that mustang dynos and dynojets can be setup to read the same numbers. This car did 114-116mph 1/4 miles 6600 rpm rev limiter and close to shifts i didnt have good tires but the speed is there for 1/4 mile and 375whp similar to a z06 stock.

 

Spend the extra and go fast 92 if your swapping intakes or 102. 92 would be a direct swap though.

 

A++ on the $500 Katech porting plus a good performance valve job. Well worth saving the extra $$$ and doing. Agreed the Fast 92/102 has far more potential than a stock LS6 intake.

ASP 25% under drive pulley worth 13 whp?

13 whp seems high unless engine is at high rpm 7,000+ rpm. Probably depends on at what rpm whp being measured more than anything else. It definitely helps rev faster, my 383 LS1 has a 25% UD ASP and it rev's better than my old heads & cam LS1 w/10% UD ATI or 416 LS w/10% UD ATI.

 

Is the horsepower gain from a fast 92-102 intake from idol 700rpm-6k or does the stock ls1 intake make more power under a certain rpm range? How about the msd atomic airforce ls1 cathedral port intake? Says uses stock fuel rails and throttle bodies. I was just going off asp claims of 13hp on a stock ls1 for the ud pulley if it does add 10whp it may be worth it.
I ran it with the new cam and no belt for just 20-30 seconds and revved up real quick like 50hp gain atleast i put the belt back on and felt back closer to stock with cam upgrade revving.

 

The small 220/224 cam currently in your LS1 is an excellent match for a Fast but terrible match for a MSD. MSD will shine above ~6,500+ rpm. If you're going over 7,000 rpm frequently the MSD a good choice provided the engine has a suitable cam & a good set of ported cylinder heads. Under 6,500 rpm the Fast 92/102 will have the advantages.

fast-92-92-vs-stock-tb-ls1-intake-gains-m6

Graph is from post #1 in thread by Scotty2000ss

Basically the old LS1 intake is inferior everywhere vs a Fast 92 powerwise. Maybe at 800 rpm the LS1 makes 1/2 hp more or something etc. The LS1 intake is very restrictive so much so back in the day ~2000 that reverse split cams like 230/224 were popular to try to get some more air into the motor. Single patterns like 228/228 etc were popular as well.

 

So the fast 92 picked up 9ftlbs torque and 14whp? I think a gear swap or 799/243 head change would be the way to go but for some people bolt ons are easier or i just havent got that far yet.

It appears this car is auto and is tuned for 6000 rpm shifts. I knew someone else with an auto, stahl bigger cam and a different tuner left the stock auto shift points. 3.42-3.90 gear would help. Does an ls6 intake add 10hp from idle-6k or is it it the high rpm range. This car being auto and mostly street driven i find it often at lower rpms vs a manual 6 speed which you have gear selection.

 

Gears and a 100 shot nitrous would get you going pretty good.......