dirt track racer 81

iTrader: (45)

I went and printed off both runs.. looks like I was wrong on what it made last time. Both runs are with my 370 with 2 valve relief flat top pistons, pulls are done in 2nd gear, converter is very loose as you can see in the graph that it finally come in around 44-4500 rpm

243 heads milled .030, 244/248 .612/.615 112 lsa, Vic Jr 1375 cfm 4150 Throttle body. Peak tq (316) is around 5700 rpm, I believe it would have made more if i would have taken it on to 71-7200 rpm.



241 heads-small port work, 230/226 .597/.56x 113 lsa, Prod Prod 85MM Intake and Throttle body. Peak tq (292) is around 5100 rpm and Hp peaked around 6000.

oldred95

I went from a little peanut flat tappet comp cam to a LT4 hot cam (218/228 duration and 112 lsa) and I really can't tell a bit of difference in lowend. At times the LT4 cam actually feels stronger and may very well be. It lugs beautifully and I have a 4L80E with the stock diesel converter that only stalls to 1500 rpms. I think most of the lag in the lowend can be cured by adding a little timing in the 70-100kpa and 0-2000 rpm range. Mine responded very well to it anyway. I do have a dual plane intake still but I think the tunnel ran effect of a single plane high rise might make the lowend even stronger yet.

00Silv4.8

iTrader: (10)

heres my only dyno graph I have so far. I will be returning once I get the money for dyno time and seeing what the end result is. Ran out of fuel at 5200 RPM



this is a 6.0 with a 221/221 .558 114. I have a donkey dick cam I will be installing once funds return. I will have more of an opinion about big vs smaller cams after that but currently I think its really based on LSA and duration. I would love more duration and smaller LSA in hopes of more gains over all. I honestly dont notice much of a "power loss" down low unless AC is on. Then again who doesnt? Also you've got a "big-ish" cam for a 5.3.

TXsilverado

iTrader: (19)

bingo

ok so here is my story...

5.3 stock cam with a tbss stall = 1.88 60'
LS1 stock cam with a tbss stall = 1.88 60'
ls1 226 112 cam with tbss stall = 1.88 60'

swapped converters for a 1.69 60'

ls1 231/239 111+2 same converter 1.75 in + 2000 DA. im sure it will cut 1.69 again in the good weather

i think MOST of your 60' is in the converter and tires/suspension. NOT your cam.

dug

iTrader: (10)

I think big cams are a waste of time unless you bump up the compression. Like already stated, you need to keep the DCR up or else the cam is a dog down low. Thats how it was on my old camaro. The dcr was around 7.5 and it was a little soggy below 3k. It wasnt that bad cuz the maro is much lighter than a truck and its 5.7 instead of a 5.3.

00Silv4.8

iTrader: (10)

maybe a waste of time with no converter?

I've never heard that one before. Even the 221 in my 4.8 wasnt bad because it pulled like a son of a bitch up top. I wouldnt have changed that cam for anything in the 4.8. I wouldnt have gone any bigger tho.

nonnieselman

iTrader: (10)

I know this aint what your lookin for but i guess it can show you the TQ/HP curve to compare something else to..

Stock LQ4 with 02 LS6 Cam
204/218 .555/.551 117.5

dug

iTrader: (10)

I was talking about cams bigger than 224. I bought a tr220 cam for my truck

05HD1500

Similar to mine with stock cam???




Here you can see the drop in low end, @ 3000 i am pulling 45 more tq

for a gain of only 25 hp...

could it be just the cam? would a custom cam of EQUAL duration, lsa etc bring back some low end?

dug

iTrader: (10)

im starting to think ls6 cams arent good for trucks. The cam was designed around the vette's 10.8 to compression instead of the trucks 9.4 to 1.