I building a lt1 with stage 3 heads and a lt4 hotcam will i need to change somthing in the ecm? its out of a 95 vette.it has 55k on it but im putting new rings in it and main bearings as well.anyone know were i can get them cheap priced? can i still use my manifolds and high flow cat to flow enough?i know i should get headers but they are over budget after my build. how much hp should i be putting to the road.

thanks :hail:

 

You will need to get some ECM tuning to maximise the potnetial of your mods. re-using your stock manifolds will work but is not a good idea in the name of performance. You will leave huge power numbers out of the equation by doping so. At least you are aware of that though.

 

ok thanks

as far as ecm tuning is that somthing i can do or do i send it to someone? ive heard the lt4 is a very good streetable cam im hopeing to put 350hp out of it. is that a good realistic
#. also who makes good rings for these things that are afforable. i looked some up online and they were like $300. thats a little too steep for rings.anything under that is probraly good. would i be better off not touching the rings rods and mains since it has pretty low millage?my theory was ,, when people sell engines they all tend to have low milage thats why i decided to look into a freshenup. whats an exhaust alternative that wont break the bank. as you probraly know headers for these things are crazy priced.

 

You can reprogram the ECM with LT1 edit. There are also mail order ways to accomplish this as well but it is not as accurate. Since LT1 and LS1 combos are so popular I bet you could find someone in your area or in the near region that can dyno tune your final combo. As for cam choice I would go bigger than the LT4. You can pretty much hit 350hp with the stock cam on an LT1.

 

realy?? how much could i get out of a bigger cam? the hot cam is a pretty big cam i thought.i wouldnt want to sacrafice reliability and tuning to much. also i was thinking later on i might throw some boost at it and its possible with a lt4 cam i believe.

 

I thought you were refering to the production LT4 cam and not the hot cam. The hot cam is a good mid range cam but most guys always wish they would have gone bigger. The hot cam can make 400hp though.

 

LT4 hot cam is still a very small cam. You got Stage III ported heads (which really doesn't say much as someone's stage III could be another's basic port job). Get a bigger cam than the LT4 hot cam. Go for the CC305, GM846, or if your really daring the CC306 or GM847. The GM cam's being bigger than the comp cams counter parts. The GM846 and GM847 are made both by Comp cams as when you recieve them they will have a CC's grind # on the cam, GM just happens to sell them and they sell them much cheaper than what CC does. Im going with the CC306.

GM847 (GM part # 12370847) :

DURATION: 234/242
LIFT: 545/565 with 1.5 RR
LSA: *112

CC306:

Duration 230/244
Lift: .510/.540 w/ 1.5 RR
LSA: *112

GM846 (GM part # 12370846) :

Duration 222/230
Lift .509 .528 w/ 1.5 RR
LSA: *112

CC305:

Duration: 220/230
Lift: .510/.510
LSA: *114

LT4 Hot cam:

Duration: 218/228
Lift: .525/.525
LSA: *114


You can see how teeny tiny the lt4 hot cam is. Trust me, most people who put the lt4 hot cam in usually switch it out for a bigger one. Do it right the first time, get a CC306 or Gm847. Both are very streetable.

 

maybee the cc 306 is a better option however i dont think it would like the boost later on and i might end up changing it again.although i could go with a 100 shot of nos instead. still not sure about it. i was told the heads are a stage 3 they have flow charts coming with them so i will see. what cfm does a common stage 3 head flow?

thanks guys
:hail:

 

Do NOT get the LT4 if you are looking for all out performance out of those Stage 3 heads. Trust me. I've got and LT4 Hotcam on stock LT4 heads and I'm seriously considering the CC306 or GM847. Just depends on which one I can find cheaper.

Stage 3 heads should flow at least 260 cfm on intake.

 

I think they are replacing the CC306 soon with a slightly different profile. The CC306 has been out awhile and I think they have made inprovments to it to keep the high end power but gain back some of the low end. They may have a new number for it all together for it though. Does anyone have any more info on this?

 

I believe the XE cams may be what your talking about.

 

Yea i think it is. I will try to find out which one one it is.

 

damnit!! I just knew someone would convince me that the hotcam was puny.

Well I guess I'll sell it.

Anyone know what valve springs would be good for the GM847 cam. I wonder if the LS1 beehive springs would work on the lt1 head. They fit the vortecs without machine work.

later,
Brian

 

Yeah, Hotcam was great for a while. But I want more, more, MORE!

 

My reason for going to a hotcam was because my previous motor was way over cammed so now i was looking to tone it down .. however horsepower is in my blood(like yours) so i will probraly end up going with a cc306 and a little spray. im not sure how to prep for nitrous yet i will have to look into it.after i get some slp headers of course.

thanks again guys.

 

can anyone further explain to me the duration specs on the cc 306? i think i understand it but im not sure . i understand the lift however just a little confused on how duration works.

 

Duration is how long the valve stays open. The long it stays open the more air can get in. This will push the powerband up. Overlap would be the time when both valves are open at the same time.

 

is anyone currently running a cc306 that i can get some feed back from?? i ant decide. how much more is it gonna take to go 306 over the hotcam? the heads i was told flow the just about same as afr 190 series heads. is that enough flow for the cc306?

 

Check out Camaroz28.com. Tons of people there running the Gm847 and CC306 on daily drivers. Hell I heard of someone running a flat tappet 262/262 cam on a daily driver.

 

sweet!! thanks pasky .. i made up my mind im goin with the cc306. theres guys who claim 330 rwhp on a stock lt with just the cam. theres others on there whom run the cam with no computer tunning. im gonna have my tunning done but at least i know it will be streetable with ease and reliable. also were can i get lt1 ecm tunning stuff/ things to do my own?

thanks

 

I don't remember exactly where I got my cable but I bought it for $35 bucks. Software can be gotten from tunercat.com as long as you have a 94-95 OBD I LT1. For 93 you'll use the same flash card type of ECM's we use in the third gens. For the 96-97 expect to pay over $550 for tuning software. OBD II is expensive, however it is possible to convert OBDII to OBDI on the LT1, just do a search, it was brought up on here before.

You'll need the definition file for tuner cat. PM for more info on that. I get my tunes from www.madz28.com. I purchased the unlimitied e-mail tunes. Just get tuner cat, download your stock bin, e-mail it to him and Ion will tune it. If you take it to the dyno and have the air fuel ratio checked and its not 13:1 he will re-tune it for free and he gaurantees a 13 rwhp increase with 93 octane and a 10 rwhp increase with 89 octane.

 

ok heres the current setup so far.
ecm harness /vette
stage III vette heads
roller rockers 1.5 to get a little low end back
ported intake to match heads and tb
bbk 58 mm throttle body
crane ignition and wires
cc 306
emission legal headers or extrude honed manifolds not sure yet.

im missing fuel delivery it has a v6 efi pump wich i know will need to be removed.my friend uses a v6 pump on his tpi but i know it will not work on a lt1. whats a good pump for this setup? what injectors? it has vette i believe they are bigger than normal f bod injectors are they good?

 

Im using a v6 pump on my Lt1 .

 

Realy?? i thought it wasnt big enough for the v8's?

 

Can you tell how good these are ported? to me i think a stage 3 job might have been a little more hogged out so to speak. not sure but it looks pretty clean.

 

Another angle

 

and last one.

 

EFI V6 fuel pump cranks out almost the same PSI as the TPI and LT1 fuel pumps. 41-46 I believe. V6 pump should be fine.....TBI ones suck...like 10-15 PSI...

 

NoUse, looks like all they did was a polish job with a little bit of port matching. Definitely doesn't look like a Stage 3 job from what I can see. Might just be the pics though.

 

my thoughts exactly. it looks kinda mild. i want to try to open them up a little more myself. Is there any threads on porting aluminuim heads. i want to get the cc306 but i need these heads to flow. if i dont port them out more would the hotcam be a better choice for me?? i would imagine around 350hp with it..sound right??

thanks
jeff

 

Get the CC306 anyway, you won't be disappointed. With that, and mild heads, you will get at LEAST 350 at the wheels.

 

ok one more thing. do vette heads flow better stock than camaro heads? to me they look pretty much exactly the same.im still not 100% sure its from a vette. i was told it was and it even came with vette valve covers and rail covers. how can i be sure?

 

hey guys were did you mount your ecm on your swap? i took my stock harness apart and made it one harness with the lt one but i dont know were to put the ecm?

thanks

 

vette and f-bod heads are exactly the same.

I mounted my ecm on top of the intake, will probably redo it though, might try and polish up the case and hang it from a custom STB I'm going to make

 

If anything, only LT4 equipped vettes had different heads and they flowed superior to the LT1 heads,

 

stage 3 heads really dont mean anything in my eyes...its what they flow thats a better indication...this is because every shop claims stage 3 and they all have different work...

The hotcam might be the best for your setup. Then again it might not be. But not everyone has the same engine specs, has the same mods. So you really cant predict it acurately.

I can tell you that a hotcam is to small for a 383 or bigger,,,however for a 350 it a lot of setups, its good...espc if u have emissions...

just my opnion sorry

 

Hmmm i heard alot of people use the cc306 in stockers. but anyway i already picked up a cc306 for 155$ not a bad price. however i havent put it in yet .....hmm ill probraly try the 306, till i go boost then switch to a single pattern turbo cam.

thanks

 

except the IRON LT1 heads which had alittle better flow, all stock of course.Of course you get that bonus of extra 70+ lbs

 

When you do the LT1 Swap, would you use the stock computer from current car or get one from a LT1? Would you have to totally redo the wiring harness?

Sorry for the questions, im really considering swapping to LT1/

 

LT1 computer and harness, splice in the few wires you need from the original (guages, fuel pump prime, power/ground, etc.)

 

yup i actualy made my own harness using my old harness combined with my new(lt1).i took all the wires not needed out of the stock and soldered heat sinked to connect the ones i used. im still not too sure how the vss works tho so i have my stock comp still running that.. to make the harness i just spliced into the power wires were the old cpu hooks and the rest are in the bulk head. i think that all the inj. aldl and powers are were the old comp is (i/p conector) and the gauge wires and fuel relays ran near the bulk heres a pick of my whole under hood harness i made... i still need a little work on the vss and reverse lights im not to sure how to hook them up.

 

It sounds to me like you did a lot more work than was necessary. What transmission are you using? Your reverse lights have nothing to do with the LT1 harness, they simply plug into the transmission.

 

lol.. yea it was alot of work but i had time while im rebuiling the lt1 so i figured i would make a plugin fit lt1 harness. its kinda like a speed density harness because it has all the power wires in it. but when it comes time to put it back in it will be a peice of cake. thanks for the info on the reverse deal. i figured it out. i did a auto to t5 swap and never connected the rev wires to the t5 correctly. were did you guys tap into the fused inj. wires and serial data wires? what did you do about your vss?

 

what headers are good and smog legal for the lt1 swap?? i cant find any that are fairly affordable. also do i need my vss hooked up to the lt1 comp??

thanks