Make sure all the vacuum lines are connected. Listen for an air leak.

 

Also, what about exhaust centerline for both of those cams? Desktop dyno just put in a number but i dont know if its right or not.
Well i fixed the engine with the 280xfi, looks a lot better now. The CC306 was a little off with the valve timing for what ever reason but both cams look VERY similar. The CC306 still puts down 35 more HP. Max HP for the 280 is 444HP at 6000RPM, and 479HP at 6000RPM with the CC306. The 280XFI starts to kick in at 5500RPM and is done after 6500RPM where as the CC306 starts around 5500RPM but will go all the way till 7500RPM and then drops off after 7500RPM. Both cams highest torque peak is at 4500RPM with the CC306 being 452lb/ft at 4500RPM and the 280xfi being 432lb/ft at 4500RPM. Very interesting. Also the CC306 still makes more low end torque CC306 being 371lb/ft at 2000RPM and the 280xfi being 359lb/ft at 2000RPM. Again not sure how realistic this is but it appears like the CC306 is a better choice. Also both cams like to be installed straight up the best. Not advanced nor retarded

 

if you have intake centerline and LSA, it will calculate exhaust centerline. Intake centerline + exhaust centerline / 2 = LSA.

Heres the numbers for both cams in my DD. I like to use small tube headers and mufflers as it makes it more realistic most of the time, but the numbers came out alittle shorter than what I'd really expect for the combo so I tried small tubes with open exhaust. IF the exhaust is done right, its not gonna be a significant gain with open headers. You cant really use TPI intake option because it assumes to little airflow. Try a standard dual plane or highflow dual plane for aftermarket TPI. IF you use HSR or similar, try a standard flow single plane intake.

280xfi makes 433hp at 6000 rpm. 425 hp by 6500 so its starting to drop off. 442lbft tq at 4500 rpm and 424tq at 3500 rpm.

cc306 makes 455hp at 6000 rpm and 451hp by 6500 rpm so its holding on strong like you'd expect with the duration split. 440 lbft tq at 4500 rpm and 413 lbft trq at 3500 so its down on torque like you'd expect with the overlap and lazier lobes.

This is abit misleading IMO because for just about anycombination of parts you run, if you do the cam iterator for max hp, it almost always picks a cam with 10-15 deg duration splits. I dont think this is the case on most engines. The headflow the program gives for TFS heads is 250cfm which may be close but that is abit misleading too because headflow alone doesnt necessarily determine engine power. I modeled a few engines on there that are known to make real life big numbers and I cant get the same on DD2003

 

Very interesting, gotta decide between the two cams, but I will probably go with the 280XFI, although the CC306 does sound badass, its not all about sound..its about how it performs!

 

First it is not a stock TPI if you have LS6 inj in it and a SLP lould mouth...
Headman longtubes? what kind of Y pipe you have or is it exit before back wheels?
LS6 inj so do you have access to a chip burner?
new cam should hit 350hp then

1.6 roller rockers may wake up your old cam

IMO get a valve job on heads with some minor porting 350hp is NP

only if the idle quality makes your car stall/launch at redlights
higher stall will consume more fuel as the rpms will be higher before the car moves, 350hp+ on a old th700 is asking for issues.
the weakest link will go first and clutches are cheaper to replace.
If it is a daily driver I would worry more about idle quality and a easy starting motor. simple parts close to stock should get you close to 300hp and no-one will know.

 

yes, technically it is not stock, but...close enough to stock, with the mileage on the motor it probably brought it back up to factory HP MAYBE a lil more. I have a Custom made y pipe BTW. As for the LS6 injectors its not tuned for em, stupid *** injector place kept sending me the wrong injectors so i decided to keep them because im building the motor anyway. I am replacing the trans with one from a buddy of mine that is selling a built 700..I am buying a built 355 long block for 3k and it comes with an ECM that is already tuned, might have to do some tweaking but thats alright.

 

Well, picking up the motor and everything today (hopefully if weather cooperates). Will be posting pictures and all that good stuff when i get it!

 

Hay guys, I'm a little late on replying on this, I just would like to say a few things about upgrading to any 305 to 350 Tpi motors, I live in Houston tx, and I only deal in selling Iroc z parts and supplies, my costumers biggest questions are what to do to make it quicker, as all these readers and askers And especially the guys wanting to do to fast upgrade without tearing out your motors and doing a project that will take days to weeks, months, or even giving up and just selling them, as 60% are just sold as projects, I don't want that to happen, I love to have factory looking Tpi motors, and that are just really quick in all ways: so Here's what you guys really need to do on a budget. That u don't have to take out your motors, transmissions, or even your rear end, that will put you guys into the low to mid 13 sec range: here's the tricks to it all, as the guys here will also concor with me,

1) SLP RUNNERS. EBAY used or new (Siamese ) cost 240

2) elderbrock headers (short) for clearance issues- cost 120-300 used or new

3) under drive pullys by march 3 pulley set cost about 100-250 used or new

4) true dual exhaust sys by flow masters (code N-10) y pipe, and dual hi flow cats, cost from 240-500 but can get cheaper ones 2/12 inch will be fine, I'll tell u why

5) 24 pound flow matched injectors, cost from 120-and up to 400 new or rebuilt, do not get used ones from your friends car, unless u actually hear it running,

6) fuel pressure regulator that will control with a screw driver coat 60 dollars

7) port and polished pentium, intake, matched with gaskets for larger ones, not stock,
Our friend at fuel inj performance from U-TUBE, he will do all the work for under 300, he's the best in the business and out if his garage! Look at his work, amazing!

8) 52mm BBK cost between 150-350 used or new!

9) you must have your chip done and calibrated to all these mods, it will cost no more then 200 or less, it will only be a piggy back dezine to go on your existing chip (prom) it much be by lab-top to get it done, it's a must, must, must, with these mods, especially with the injectors,

10) if it's in your budget? Get a transmission kit by B&M, no more then 90-120 done at ANY transmission shop, it will help to not kill your shift points, firm shifs is a must,

11) a k&n air filter sys, there are several ones out there, or u can make your own design, but with a real K&N filter, not thoes cheap tywan styles that have colors,

I guarantee that your 5.7 will do low 13 seconds to a out 13.2 to 13.4 all day long, and with slicks? It should break the 12 sec range with having your ac equipped, but off turned off when at the track, da,

A 305 Tpi will do about 13.5 to 13.6 all day long as it will be much much lower, I just don't wanna make it to say higher the that,

In 1989-1990 the Iroc z 1le that was tested w/a roller motor, 305 standard 5-spd done 13.7 in the 1/4 mile, and had just a few of these mods, and the 5.7 done (1le) 13.5, and it was tested by the best of motor trend magazine, but remember these cars had no ac installed, and was made to beat Steve saleens mustangs back in the day, and they sure did, on the track and on the streets, the Camaros had the N-10 package, the G-92 rear end (3.45) and so forth,

So doing these modes, your Camaro (Iroc z) will look so stocked when your friends open the hood, you will be amazed. I wish I can post a pict of mines, I did all of these mods but a few nkt yet done, and I ran a 13.1 with stock headers, have ac, and I do have a 5-spd, but with a 5.7 liter I put in from a 89 Gta Trans am, that has a oil engine cooler, and a 3.27 rear end, that looks nice,

I can go on and on on what to do, as far as heads, cam, and all other top end parts? It's a lot of money like the tunnel ram style Intake, which I sold mine, So if u do go that route? It's not easy as said and done, as I have a ton of costumers who Camaros are still in working progress, and still under a cover, or just collecting dust, don't take on such a big job unless it's at a good shop and that you'll know that they will do it much faster then a few months, and get your money set first, don't say? I get paid on Friday, and when Friday comes? It it's a whole new world..... You have to eat to..... I so hope this helped out you guys!
John gypsy from Houston tx.....

 

Orr89 I know this post is from awhile back but do you mind sending me a message I have a few questions for you . I’m looking on building my first gta and I’m new to the older car scene I’m more use to wrenching on tuned diesel trucks . Much appreciated