Im getting ready to order a comp xfi cam for my 87 iroc 5.7 tpi motor but not shure which one. I have a set of afr 1041 heads flat top 10.1 pistons, and 1.6 roller rockers, msd, headers,mild tpi porting, afpr, will be redoing my prom to match everything up as well. I will also need to keep in mind ill be stroking it to 383 this summer or winter. Im thinking of either the 570/565 that works in the 1800 to 5800 rpm range or the 576/570 that works in the 2000 to 6000 range. AFR lists the heads as best in the 2000 to 6000 range but the tpi set up is not to good at 6000 so what do you guys think I shoud go with for best all around power???

 

When doing the 383 swap will you keep the TPI? Is this a ported stock TPI setup? Still on stock runners?

 

yea im going to keep the tpi and just going to put in a 400 cranck and the pistons to make it a 383. the tpi is ported some and i siamesed the stock runners but I will be getting some aftermarket runners and intake. Im keeping the tpi and stroking it to make a neck snapping torque monster.

 

I would go with the xfi 280........LOVE IT, great power throught the whole rpm band, and nice sounding idle.....that cam would complement you motor now, and you future 383 plans nicely.

 

well I just ordered the 280 lol. did you have good luck from the pcmfor less chip? how much and cand you send it back and have them tweak it for you?

 

Sweet, you'll love that cam....oh did you order the beehive valve springs with it...it takes a special spring, can't remember part number....and special spring seats and accessories (cause the size at each end, shaped like a beehive)....

PCMforLESS did a great job....I've used them numerous times. The first time you use them it will cost you like $250 I think. You send them a build spec sheet you can print online on thier site, then they send you a 'piggy back' chip. You take your stock chip out, put your stock chip in the back of the piggy back unit, and push that into the computer. Works great. They burned my first program with an old build I had, got it right on the first try. This burn I sent the unit back to them and with an update sheet, cost my $57 for the reburn, got it dang close if not right on with the build I have now. I'm sending it back one more time when I do a gear swap and trans swap to get another update, will only cost 57 for that one too. you can send it back as much as you need. I think they sell tuning packages too, not sure on how that works....like 5 free reburns or something.....you might have to call them on that. I have a bunch of friends with pcmforless tunes also, turned out great.....one of them a '94 camaro running 10's....had to do his twice to get it right,but one hell of a build.

 

sometime i wish i would have gone 383 instead of 355...... but hey i love how my car is... goodluck with the build... you will love the tpi's torque... i know i do...

 

That 280 is gonna be abit much cam for a 350 at the moment but will be better suited to the 383 down the road with a full ported TPI lower and siamesed runner.

 

I disagree a little (but understand where you're coming from) with you on the bore/stroke of motor, depends on how you build it, for sure better suited for a 383, but run it in mine which is stock stroke....but for sure on the intake upgrade, that is a must.

 

Thanks guys I feel very confident in my selctions now, and getting very excited to recive my parts and push the gas pedal the first time. 91 do you think Ill have to use the beehive springs on the AFR heads? I have a set of 1.6 roller rockers and if its just the rocker that rubs on the top of the spring retainer I wont mind to grind a little on the rocker to make it work. The rockers are just the blue proforms so I dont mind to grind a little on them. I might have to order a set of regular style rockers anyway cause I read on AFR's website that with the guide plates you dont need to use the self align type rockers that have the 2 little washers on each side of the roller tip, it said something about a conflict with them and the guid plats so ill probly just remove them by grinder or pressing the pin out. I hope I dont have to use the beehive springs because with the cost of the gaskets and stuff I will be held up another 2 or 3 weeks waiting on some extra money lol. Is the rocker to retainer clearance the only reson for the beehives? And thanks for the info you guys made me even more excited lol!!!!!!!

 

afr's comes stock with a lift of .550 you can get their upgraded spring and rev kit and should be over .600 lift with the springs........ thats all you need......

 

Sounds like a nice build either way. 350 with TPI will make engine feel bigger than it is at certain times. It thought AFR's can handle 0.6" lift stock. Their website list that lift amount under basic component package. Rev kit just uses stiffer springs and guide plate for more stability right?

http://www.airflowresearch.com/index.php?cPath=24_29

 

well comp cams suggest that you use the beehives...it's the springs matched for it....I used them cause that's what they told me, but if you used a comparable spring you should be okay.....
here is the part numbers you would need for the whole setup of comp.
cam.....08-67-8
spring...26918-16
retainers...787-16
valve locks 601-16 or 648-16
cup seat 4705
shims (if you need any) 4753

your springs that is matched to cam is 125#s @ 1.800 installed height 367#s @ 1.150 and coil bind at 1.110 372#s per inch
if you get something close to that it should work. I know the comp ones are expensive but I think worth the wait.....
like 88fastgta said, check how much lift your heads will hold, I would of thoght afrs would of allowed more lift that .550 but dunno for sure. The rev kit is another idea you could use. It'll all be worth it in the end, trust me on that. oh, make sure to get your computer tuned, and also you'll need bigger injectors...like 30lbs or something close. And, a better intake setup eventually, and on your valve guides, just make sure whatever you use the rockers are not going to side step off valve end. oh and if you have not already, use umbrella style valve stem seals, not o ring style, but you probably already have those. You'll need a timing chaing set. And put the cam in straight up, DO NOT advance or retard the cam timing...it is build in with advance already in it....you'll get a card in your box that says that anyways. And if you use pcmforless.com for tune, remember that you need to put the timing at FACTORY setting, do not adjust it at all....i tried once and just one degree really slowed it down, and they set everything to stock fuel pressure so get the right size injector...I would say a 30lb per hour personally. Others will say 36 or 38 or 40....but it depends on how you calculate it....I base it off RWHP not FWHP....or just call pcmforless and ask them what size they suggest. that's what I did. Car runs in the low 12's at high altitude on street tires now.

 

That's what I thought too....those heads should handle the lift just fine...

I would try to get the beehives then if you could....cool spring. when I called comp that was the only spring they recommded, not even any of their standard style springs, something works different with these new srpings.

 

Dont need the beehives...just the AFR upgrade 8019 spring. That spring was designed for XFI type lobes and is used on even more aggressive LSx type lobes. I've used them on my 383 that revved to 6800 with no signs of valve float.

AFR heads need non-self aligning rocker arms. They use guideplates so self aligning are not to be used. Use hardened pushrods.

This is what I'm refering too, an intake upgrade is a must. TPI intakes without siamesing are not adequate for a 350 motor and that cam size. That cam would benefit from a HSR/Miniram intake that wants to rev over 6500 rpm. Its a tuneable cam that will run ok, but its full potential will not be seen with TPI unless its full ported/siamesed type setup like the california boys run

On a 383, it still would want a better intake as it will peak near 6000 rpm with 280XFI cam. A full port/siamesed TPI could possibly support 5500-6000 rpm on a 383 so the cam is not that bad of a mismatch. The 268XFI is much better choice for a 350 TPI motor and would still work well in a 383 TPI setup. A 276XFI would be perfect for a 383 TPI but that is a custom grind, which shouldnt be any extra money through comp cams.

 

IMHO I would use the AFR 8019 springs as a minor increase in price for the upgrade. Running them on motor and spinning it to 6800+ with no problems.

As to the 10.0:1 compression I would have AFR mill the heads some and get the compression up to between 10.5 and 11.0. With 10:1 you are in no mans land. To high for the lower octane gas and a little low for max performance with the higher octane gas. You now have a chance to get the best performance from your motor before you order the heads. I'm running 11.1:1 with the AFR heads and 91 octane gas. No reason to leave horsepower on the table for a little more money.

 

When he goes 383, the pistons need changed out so he can go with flattops to make 11 to 1 with AFR's 65cc chamber.

So you can mill the heads now to get compression on the 350 and when you do 383, get some mild dish pistons to lower compression back down, as the increased stroke is gonna bump you back up with a flat top. OR you can hold off on the milling, run 10 to 1 and then when you go 383 get flat tops and enjoy 11 to 1 compression.

Its up to you, but i believe there are alot more flat top pistons available for 383's. I havent shopped for dish pistons in a while. With a 355, a -5 cc flattop gives 10.8 to 1 compression with a 60cc milled chamber. I dont know if AFR can go lower than that without angle milling. If you go 383, with that 60cc chamber you will need a -12cc dish for 10.7 to 1. A -7cc flattop 383 will be 11.3 to 1 which may be a touch high with that cam.

If you can get a 10-12 cc dish piston you can mill your heads now and gain some power.

Else, i'd hold off.

 

I gotcha. I wasn't sure about the AFR heads....I don't run them. But I do run the HSR....and if you can afford that, the airflow is great. Mine was ported even futher and the motor just breaths freely

 

Great info and looks like you guys have debated the same issues I bounced in my head for the last 6 or 7 months when I decided to go ahead with the heads, cam, and stroke. Thanks alot and yea when I go with the stroke im going to be asking agin about the compression because thats one thing I dont really know for shure about. The runner and intake upgrade is forshure going to be maybe even b4 the stroke I knew I neede it bad and since I went with the 280 cam I probly will do it b4 the crank. I am now in the processes of checking on reprogramming the prom and might even go ahead and get my own stuff to do it but theres so much to learn that I will probly just get PCMforless to do it this time and when I get done with my upgrades start learning how to program then and when I get good Ill tune your guys free anytime lol. I also will probly go with 30lb. injectors as well thats what accel reccomended when I called to ask. I have venom's right now but there just the stock 22lbs. but Im going back with the venom because their prices are much better but, I saw on the net some new boschII or III new style that I can use and their also only around $200 a set for any pound. Have any of you heard or used thes new injectors??? As far as the cam I was going to go with the 268 but since the one guy(sorry I cant see your screen name on this page) has used the 280 and had good luck and also mentioned the nice idel I thought id go with it. Another thing that influnced my decision is that if for some reson someday if I want to remove the TPI (very unlikely, they just work so good and reliable and easy to work on and besids after I mirror polished it DAMN it is truely the most BEAUTIFUL induction system imo that is out there besids a blower) I can slap a victor jr. on there and it will be perfect. The self align roller rockers I have now will conflict with the guid plats so do you guys think it would be ok to just grind those 2 little washers off the tips (the things that make them self align) for temp untill I can get a new regular set? IMO I cant foresee any problem that that would cause but, let me know what you guys think.I also just found a set of 8in. MT slicks that I'm going to buy (at the track even b4 any upgrads wheel spin was very bad my worse enemy off the line.) but theres only one concern I have about them which is Im afraid with the slicks that im going to start breaking parts, rearend, driveline, & tranny parts. I bought the Richmond powertrax locker last year and absolutly love it but I would hate to break it.I only have the 7.5 rearend and we all know how weak thoes are. Im going to get a spare driveline to keep with me and upgrade my u-joints to the strongest possable. But agin thanks everyone for your input, I love this 3rdgen site it has helped me ALOT, and I'v helped a few myself. But let me know wht you guys think about the rockers, slicks & bosch II or III (im not shure if it was the II or III that will now go right in place of the stockers) injectors. And what do you think about the poundage? I have the TTS Datamaster diagnostics program I can run on it and it has a duty cycle and a couple other mesurement on it that says good for helping to choose injector size. THANKS AGIN EVERYONE !!!!!!!!!

 

let's see if I can get some of those questions in here.....the bosch 3 is a ls1 style injector, and runs at 50lbs or something, so a 30lb injector would be actually a 27lb or something if you ran near the factory 43.5 lbs. I would stay with the older style for sure.
I don't know about grinding the alignment tabs off of the rockers....never dealt with that....
The stock rear end is weak, but there are some things you can do to improve it, such as moser axels(or any stronger brand), a studded girdle diff cover with bearing screws caps (most important), a zytanium center pin, shock proof gear oil (or really good gear oil), also if you look at where you axel tubes go into the center differential you'll see two welds, one on top and bottom....what ya do is finish the weld all the way around the tube....that'll help to keep it from flexing. plus the cam will have a little less power on the bottom end, so it won't spin as badly right out of the hole like stock....but it'll make up the difference in power around 2800rpm or so. you might wanna get a 2500 or 3000 stall when you get the chance.