jatsfirebird03

What is the biggest cam i can run without a tight tolorance on my stock bottom end?

PNYKLR-TA

iTrader: (1)

read the very top stickied thread, its call cam swap guide. its really helpful, thats why it was stickied!

NightTrain66

iTrader: (7)

as far as piston to valve clearance, you can use a pretty big cam and not have a problem. There are 250+ duration solid rollers with .630 lift that will fit with stock pistons and not have P/V clearance problems. That doesn't eman it is the cam for you to run. A stock bottom end will not last long spinning 7000-7200 RPM to make use of a cam this size.

The hold up on cam selection is usually what RPM the stock bottom end can handle and stay together.

Almost everyone will consider 6300 RPM to be safe and agree that is you have problems shifting at 6300 RPM, you probably had a wounded bottom end and it would soon have problems even shifting at 6000 RPM.

Some consider 6500 RPM safe as a few people have gottem away with shifting at this RPM with no problems. For 5 people that say they shift here with no problem, you can find another 5 people that has had problems shifting here. Previous engine traume (overheating, oil changes, etc) will play a role here but some well kept bottom ends have problems here as well. The rod bolts and balance job was not really menat for this kinda RPM and the 400-420 RWHP that usually goes along with this RPM.

VERY few have success shifting at 6700-6800 RPM but there are a few that have done this. These guys are the excetion more than the rule and if the engine "must" last, do not even consider shifting here as you are playing with fire.

Shift RPM (explained above) and vehicle weight, gear, stall, drivability, emissions, driving style, idle you can tolerate/want, how much low end power you can sacrifice, etc are ALL very important.

Lloyd

GreatWhiteZ28

iTrader: (15)

Loyd has some very usefull info...I went with a Comp XFi 230/236 .571/.576 113LSA....it's not too big and not too small...kinda like a happy medium for me

slick1851

Contact AI and have them cut you a custom one!

96capricemgr

iTrader: (1)

Understand shifts occur a couple hundred rpms after commanded with the A4 and that you need to rev a few hundred rpms beyond peak power to keep the engine in a good average powerband. All that said you are probaly best to stay BELOW 230degrees as most cams in the mid to upper 220 range will be hitting 6400-6500 during the shift if you command it somewhere around 6200rpms and that is with a built tranny, expect more rpm rise with a stock tranny.

Understand too that folks are quick to defend whatevcer mistakes they have made, as such you will find a lot of guys defending BIG cams in stock bottomends and making excuses for why guys with smaller more reliable setups are faster.

jatsfirebird03

so what cam would u guys go with.. I have a lt4 heads intake, rebuilt stock bottom end with 3000 miles on it a rebuilt tranny built stronger,long tubes and borla,aluminum driveshaft,and a hotcam now in it?

firehawk238

iTrader: (1)

honestly with a stock bottom end id stay with the hot cam. especially if it is a daily driver. if all that is already in the car and running, i wouldnt spend the extra money to pull it and go through it all again. id just add a 75 to 100 dry shot and call it a day. just me though.

karl

96lt1m6

iTrader: (31)

the beginning of this thread is the number 1 reason most people OVERCAM an engine!
sometimes LESS is more.................................

StealthFormula

iTrader: (35)

I pretty much have to agree...you could go with something a little bigger or better than the hot cam that you already have and still be safe with the bottom end but not worth the money and time to swap IMO.

I sometimes wish I just would have left my cc503 in there and just sprayed the **** out of it because the heads/cam swap was just a real PITA and made me appreciate what I already had so much more.

Pro_built7

iTrader: (9)

but now you probably appreciate the h/c swap a whole LOT more ! lol

Bumper Dragin Bird

iTrader: (8)

i got AFR 195 LT4 heads with Comp cams XFI 584/579 lift 292/300 dur. in my car. got good throttle response and top end. Off the line no problems and at a forty roll. I got a th350 trans with a 2500 stall, 373 gear. sounds pretty wicked too. Flat top pistons, no problems with valve clearance

LT1 TRANSAM

I have the same cam in a 383 and i also have a 350 turbo trans i'm stuck on what stall to put in.How do you like that cam and how does the 2500 react to it.I got people telling me to put a 3000,3500 and even a 4000 stall in.

NightTrain66

iTrader: (7)

pretty much anything in the low/mid 220 duration @ .050 and NO LARGER than 285 advertised duration range will work pretty well for you.

CC 503 is about as wild as I would go on a catalog cam.

Lloyd

slick1851

Get A Custom Cam!

slick1851

Hotcam is dinsour junk

LSWHO

iTrader: (1)

I agree here.

But, what the hell is this?

Fixxer99TA

iTrader: (5)

Dont you know what Dinsour means!?!

I even run one and I will admit its almost the worst choice considering all the custom cams out there these days. But it was moderate and thats what I wanted, and I got it. Now when I do the heads this winter, the cam will definitely be custom.....More than likely an LE2 or 3.

96capricemgr

iTrader: (1)

Someone tried that on a stock bottomend and found the power still climbing at 7000rpms, meaning it is a really bad choice for a stock shortblock if you expect it to live atall. Even on a 396 it needs to rev beyond where we have all agreed is the limit for a stock shortblock, for those who don't know it, displacement tames cam, bigger the engine the bigger a cam you need to turn the same rpms.

jatsfirebird03
Far as the LT4 heads, well you already screwed up in a pretty big way with those. Probably the only good thing about those is the hollow valves. They just do not work that well, especially not on a 350, most of the bench racers who want to believe they are awesome will even admit that with stock displacement they are a bad choice. If you got the whole GMPP kit the rockers are limited to .550, most of the better stuff you are going to look at now will bottom out the rocker slot and break stuff with them.

Don't like my comments, maybe it would help if you research results, the LT4 HOT package heads and cam is usually good for 320-330rwhp, the average ported LT1 heads setup is well over that and the good ones go over 400rwhp, basically making at the wheels what the LT4 kit makes at the flywheel.

jatsfirebird03

well I bought the car with all the lt4 stuff on it, i think they are very good for what they are though. I am going to get them done by loyd or AI next month but was looking to save some money with an off the shelf cam. and yea it was 336rwhp with the dyno from BLUECAT whitch they say reads alittle low.over all i am happy with the setup that the car had when i got it, the hotcam and lt4 but wanna go faster and have more power.