hey everyone,, i need advice, i got an old style sbc(like an 85, .30 over,,wich gives me a 355,with flat top pistons i want to run a tpi set up on it, the guys who rebuilt it,dont touch fuel injection so they're not the best to advise me, at the time they buit it,it was supposed to go carb, so they told me the camshaft wouldnt do for a tpi,the cam is( comp cams cs xe274h-10 .490 .490 do i need to change it? i got a tpis bigmouth intake,,slp runners,holley 58mm throttle body,corvette injectors, .... with a chip that was done by the previous owner of the tpi set up for his iroc l-98 350 motor, now what i wanna know, is,what to do to make this work properly, what kind of camshaft? what specs for the heads, i'd like aluminum heads,dart or edelbrock seams like the way to go,but if you know better priced heads that arent crap,id like to know ,but basically tell me the specs i need,is there any mods to do to the motor? like for knock sensor,can i use an existing hole? do i need to change the chip just because its 30 over or different heads and cam than the l98? im no engine builder but i can sure reassemble the top end of a newly rebuilt motor,i just wanna know what to throw on for parts, so... head specs,cam specs to match it,whatever needs to be done for computer and to the block. some people tell me im wasting a good strong shortblock by turning it into a tpi! am i? i know it wont rev as much has a good ol carb,but with all the aftermarket stuff,it must be working pretty good no? thanks for any info,,and please,those who dont have a clue,stay out of this for it will only confuse me! experienced mechanic or someone who built the same kinda projects only please and thank you all!

 

cam is alittle big for TPI but it will work with a good tune. If you already have it, just run it. Heads if you want Dart, go platinum pro 1's in 200cc aluminums. the 180cc's would work well with TPI's short rpm range so consider them as well.
Dont rule out Brodix race rite's or IK200's either but watch the valve guides on the IK's they have been known to have issues. AFR 195's are very popular and they work well. So do the 180's. SO do Profiler 195's which are a great bang for the buck price.

If it was my build, I'd be more inclined to do the AFR 195's for TPI with that setup or the Profiler 195's from Chad Speier. Both are great heads for the money and usually outpower the other brands in that rpm range.

Just find a hole for the knock sensor, it should have one you can use. Chip will need retuned for the heads/cam/intake mods. What system are you using? MAF or MAP? MAF will tolerate mods more so than MAP but still need tuned.

Do you have to use TPI? YOu can use other EFI intakes like stealth ram or miniram or Edelbrock Proflo XT. Much better match for the cam and makes more power than that TPI system will. Just a suggestion.

 

also , i have a set of edelbrock hshortie headers with special 3rd gen f body y pipe, that goes to single 3 inch exit, can i keep that or do i need absolutely true dual? i hate the idea of stuffing dual exhaust under a dropped 3rd gen, plus my floor is already truck bed coated with welded frame connectors that could be in the way, i dont wanna modify anything underneath,is single 3 inch enough?

 

thanks for the reply buddy, i know about the stealth ram and stuff but i already have that tpi set up here and id like to use it,looks nice under the hood,plus its paid for!lol its a maf i think,,is it the one with the bosch sensor in front of the throttle body
tube?

 

holy jumpin! i was just looking at your twin turbo build up! thats what im talkin about!! great stuff man, exactly what im planning for my 68 camaro! now back to my lil tpi 3rd gen!lol

 

Ok, use the TPI then since you have it. Still a good system to make good power to 5K rpms. heads, stick to any of the big name brand 180-195cc heads or so. Its really your choice and how much you want to spend. You likely wont see a huge difference in power between the brands.

I've used the AFR 195's on my 383 and 401 and they did great. The faster velocity ports seem to make abit better power on lower rpm setups, like TPI. I've seen them used on countless builds here and do great things. I've also seen the Darts perform well along with Trickflow and some of the Brodix heads. Profiler as well on some hotter motor setups but should do great on a 355.

 

ok,will go with afr 195, my car was originally tbi,,, i assume the pump in the tank is not good enough right? and rubber connections ,do they need to be changed to all steel?

 

TBI usually runs lower pressure I think, so it would be good idea to go to a 255lph walbro type fuel pump and such. Does the car not have hard fuel lines on the body? It should go rubber from tank to hardlines and then to rubber hose lines to the rails if I remember right...I thought they all got those but I'm not sure. If not, it may be best to run braided line all the way to the front fuel rails.

 

ok i found a tank from an 89 iroc stock tpi pump, is that ok? also have original tpi lines .so im good on that,my harness is from a automatic car, mine will be 5 speed,can i use the same harness? i still have all the dash wiring in my trans am with connector goin to trany, so i got motor to ecm harness from donor tpi iroc, and from the firewall connector,what i have is the original or the trans am,do i just connect em together? repin some stuff? or do i need the whole underdash and fuse box from the camaro as well? i dont have the same gauges and options as the camaro since mine is a t/a ,man is that a headache for a first tpi swap,thanks to you that s helping me out.

 

Stock pump should support but its always nice to make sure its a fresh pump. Dont want it to fail on you.

Should beable to use the same harness, but not 100% sure if there is anything special with the clutch pedal stuff for neutral safety or not. For tune, just use a 350 L98 manual trans code from a vette, or a 305 based TPI 5speed setup and modify it to work for the 350. Camaro or trans am, they used the same electronics for the most part. Motor to ECM harness should all be the same.

 

ok thanks, well my car is already standard with clutch column safety switch all functional, that shouldnt have anything to do with ecm right?

 

my car is an 86 ta originally throttlebody 305 5 speedmthat had been converted to carb but kept same trany,,, i just want to drop a tpi motor in there with its ecm and wiring, i just wasnt sure when the tpi wiring ends and meets the cars original electrical harness.maybe i should buy a book! but youre of great help so far.

 

yeah the wiring isnt my thing. I never did manual swaps, just kept automatics. I know the motor side of things doesnt really care as long as the wiring harness is for the type of ECM you use. Mass air flow or manifold pressure. I'd run the MAF stuff since its easier to tune IMO and works well. But finding good condition MAF's is alittle harder to do and new ones can be pricey.

 

thats what i have now on my set up,,,maf, i think, the one with the big rubber/plastic pipe and bosh sensor in front of the throttle body that keeps you from using a k&n filter!!

 

Excuse me chiming in here. MAF will limit your power capabilities and yes, TPI will flow alot more air than the tiny MAF sensor can support. That's why serious TPI builders use Speed Density(MAP). Tuning is just part of the deal. The cam your using is really very small. Look at my sig. This engine is very streetable and puts LS1s in the dust. If you want a more mild idle, go with something around .500-.520 lift and 220-230degrees at .050. Of course use a hyd roller cam. Flat tappet went out with the dynosaurs and will limit your power and cause you grief with the lack of ZDDP in current motor oils.

I agree with Orr on cyl head choices. The 195-200cc heads will definitely want the bigger cam lobes. For more info on cam choices, go to TPIS. They are pioneers in high horsepower TPI.

Edit: Oops, forgot my sig doesn't show cam specs. The cam is 240degrees at .050 with .560 lift using 1.5 rockers. This engine makes strong power to 6,500 and I shift at 6,800.

 

ok thanks,then what do i have to do to switch to map?what do i need to change,,,the ecm has to go as well? are fuel rails the same? wiring? is my cam allright or do i really have to change the cam,everyone says its too big for the past 6 months,now you tell me its too small,,,can i take all that for a ''its just fine,use it''? that would relive me.

 

MAF will only limit hp potential if you are trying to get up over 400whp which is hard to do with any TPI setup. I ran stock MAF at 400whp and went to 3.5" MAF and didnt pick up anything.

ASE loves big cams and so do I but unless you have a good tuner, it may be better off to stick with something somewhat mild. That 274H cam is a nice cam.

I like roller cams as well due to the reliability and increased power they make. However its a pricey conversion due to lifter prices ~550 bucks. cams are in the 250-300 range for shelf grinds.

I tuned my friends car which is a overbored 350 to 360" with old AFR 190's and a 280xfi cam, which is 230/236 .576/.570 113lsa. Idles great although pretty choppy, streetable enough to drive around and is capable of high 11 second passes but he runs Stealth Ram and can pull to 6500 rpm if the valvesprings were stiffer. TPI would cap that powerband.

 

and yeah,what about my exhaust question,, is headers and single 3 inch alright?

 

Depends on how much power you want to make but given the current motor build, it will work ok with a single 3" with a good high flowing muffler. I'd prefer 3.5" but not many sell anything like that.

 

ok thanks

 

are the afr worth the extra 500 $ over edelbrock rpm heads? if so ill go afr,if not,well i wouldnt mind putting the extra 500 bucks somewhere else.

 

Have you ever seen edelbrock heads? If you have you would know just by looks alone! That was kind of a joke no body picks heads on looks but they look great. Afr are ONE of the best flowing and best made heads. IF you dont have emmisions requirement im sure there are other options. But as far as emmission heads they are the best out of the box. You will have to port the edelbrock heads to flow the same and make the same the H/P as the afr's which is why so many people recommend them. And everyone has their oppinion on there customer service but I worked with jerami, and he was great!

 

theres a guy here that has connections on AFR heads, and you can get them around 1300 complete shipped. I paid 1450 shipped back in 07. Other heads out there are in the same boat, 1200-ish complete. Theres not much out there that will save you a bunch of money and AFR is one of the better equipped heads for hydraulic roller cam motors out there that you can truely bolt on and run well. They have 8mm lightweight valves and great small diameter double springs. IF your not running a roller cam then you would have to downgrade springs and wont need the lightweight valves, so other heads out there with basic flat tappet springs could suffice and be cheaper.

 

ok thanks, ill let you know when im at that point,if you can hook me up for a set of afr for 1300 it'd be great!

 

I lost track of this thread. Orr is right, I do love big cams. LOL. And yes, you need to know cam selection and tuning to go this extreme. The main thing to remember with TPI is to keep at least 112 degrees lobe separation angle(LSA), otherwise known as lobe displacement angle(LDA). The cam needs to match inlet runner volume and desired operating range(RPM). But by using a well designed roller lobe with sufficient LSA, you can have excellent top end power and still maintain drivable low and mid range torque.

To change to MAP, or speed density fuel management, you need to swap out the ECM. One is not compatible with the other. The factory intake, including the tiny MAF sensor will support 325HP. So to support Orr's point, you don't need to go as far as swapping out fuel management systems to get a significant increase in power.

 

so,whats the final verdict,,can i use my cam or not? buddy at comp cam says no,and ase tells me i need at least 112 lobe separation,,, mine is 110 ,and the rest of specs are pretty close to the one they have for tpi,, can i use it or not!? if so,thats what it'll be, 355 55 86 block ,flat top pistons 10;1 balanced,with afr195 heads ,tpis big mouth intake,siamesed slp runners ,30lbs injectors,maf system,58mm holley tb ,siamesed plenum,edelbrockheaderswith y and 3 inch cat delete single ehhaust passenger side exit.does that make sense!? will i have fun?! with a 5 speed and 3.42 gears posi. WILL THE DAMN CAM WORK OK????? I HAVE 50 DIFFERENT ADVICE HALF SAY ITS GOOD HALF SAY ITS TOO BIG OR TOO SMALL! OR NOT ENOUGH LOBE SEPARATION,,whatever that means,,im not a mechanic,its why im posting here,,,worst case senario?what can go wrong with that cam?loose a bit of hp that ill never know i lost?or is the motor gonna knock and puff and suffer,i really need to know if i want to start putting this together

 

all i want is a powerfull street car to beat the **** out of,and drift in the turns,youll never see me at a drag strip or on a dyno,i'll be on the street,getting chased and in parking lots burning rubber,,,thats the closest thing we got to autocross down here,thats what i'd like to do,but there are no tracks around.i got all the info i need from you guys,and i thank you very much,,,the only thing i need you to agree on now,is the cam,can i use my xe274h-10 without fearing the worst

 

if the chip is tuned right, it will run just fine with 110 lsa. 112 and higher just makes it abit easier to tune at idle. Less overlap keeps closed loop operation with narrow band o2 sensors happy. You dont have to run closed loop and in fact, most big cam setups shouldnt. Its totally up to you.

I ran 109 on my 383 and it was just fine in either mode but I chose open loop due to an o2 timer issue that I think I could solve now, but got frustrated with it back then and just went open loop. either way you could daily drive that car, it was very driveable.

 

ok,,this fuel injection thing is all new to me,,,closed loop ,open loop,doesnt tell me much,isnt one of both when tou start the car,before the o2 sensor gets to a certain temp and then it switches to the other mode that then the computer moniters every sensor for a/f ratio adjustements? so you mean with a big cam you just let it run wide open like a carb instead of having the ecm constantly retune the motor? i bought a tpi info book,just starting to learn,,there is quite a bit of science to it,but its very interesting,,,,,i had my motor originally built for carb i have everything here but the heads to make it run, supposed to be good up to 6500 rpm and over 425 hp,,,would be easier,,, but now that i started looking up the tpi stuff,and everybody around here including motor shops tells me its too complicated to make it run right,,,they kind of stumped me,,now im on a role!,its a challenge for me to build it tpi and proove em wrong!!!! every single tpi cars in my area have been converted to carb cause people think its impossible to get to run right,,,i just think they dont try hard enough and they are affraid of reading and learning, with your help,,a few books,the net, and some patience,i'm ready to toss that carb set up and do this tpi thing! carb is ancient tech from the past .so to run open or closed,,,does that get decided with the chip?the way u tune it? plus i was looking at aldl to usb cable to hook up my laptop on,,,can you then ttune is on the go with the laptop,or does it still need a chip burned,,,i'd like to be able to learn to tune myself,either with laptop if its doable or whatever i need to burn chips if you can tell me,,,,there are young ***** guys here that charge 400 $ to do tpi chip for guys like me!!! ,im sure if they can do it in their honda envirement,,,i should be able too!

 

Yeah the car intially starts up in open loop but once it reaches temperature and hot o2 sensor, it goes to closed. What I do is just change the settings for the temperature so that the motor never is "hot" enough to get into closed loop. I believe factory settings are around 104 deg F coolant temp. I just make it 300 deg. Motor never gets there, so never goes closed loop.

I take out the narrow band sensor and add in a wideband o2 sensor with air fuel gauge. I tune by that. Its basically an electronic carb, you tell it exactly what fuel you want it to see and the ecm will never correct for it. Comes in handy at idle with a big overlap cam, because of reversion effects the o2 sensors see excess oxygen and start changing fuel around when it really doesnt need to. The spark plugs tell the true story so i check my plugs at cruise and idle to verify they look good.

TPI is not complicated. EFI is not all that complicated for the most part. Sure, the code and algorithms are pretty challenging to understand but you dont really need to know all that. You just need to know what changes to make in TunerPro RT software or TunerCat and understand how those changes effect motor fueling. Its fairly straight forward, it just takes time to play with it to start seeing the patterns and understanding how certain things work.

Because of the age of these cars, not many ppl tune them. Most shops tune LS1 cars now, and some can do LT1's but TPI is left out in space.

If you bought the chip adapter, chips, burn programmer and aldl cable from Moates.net and download the tunerpro rt software, you can start tuning your own stuff.

 

The only problem I see with that cam is that it's flat tappet. flat tappet at any given LSA and duration is going to be slower to open and close. This leads to increased overlap. It's the overlap that causes reversion and causes power loss in the TPI. The power loss will be at lower rpms and simply create a very narrow power band. Your engine will scream from about 3,000 to wherever it runs out of air. Where it runs out of air will depend alot on heads, what actual TPI base you run and whether or not it's been ported to maximize flow, and what runners you use.

Flat tappet cams in today's world just don't make sense to me. The oil companies by order of the EPA are phasing out ZDDP from motor oil. Unless you add ZDDP or use a special(read expensive) oil, you are certain to suffer early cam lobe failure. And that's if you don't destroy the cam right away by not properly breaking it in. And all this trouble for a cam that will never perform as well as a hyd roller of the same lift and duration. I would urge you to consider switching to the XR270 or even the XR276(if you are going to run big heads and a high flow base and runners). You will get a wider power band, more peak HP, better runnability, and alot less headaches. Of course the hyd roller costs more, and if you are using a non roller block, the lifters will push the cost up even more. But in this case, you definitely get what you pay for.

Yes, the cam you have will work. It just won't work nearly as well as either of the roller cams I just mentioned.Worse case is that you find you hate this cam and have to do a swap. It's really not that bad.

 

thanks,well the base is a tpis big mouth,siamesed slp runners with matching plenum,heads are gonna be the afr 195's 58 mm holly.if what you say happens with my cam,,,destroy the mlobes or whatever,,,is it gonna destroy the rest of the engine? or can i try it for now and swap later if it really sucks,,cause i have an old non roller block.im not rich,would suck to have to swap everything.

 

millions of people are using older motors with flat tappet cams,are they all in trouble? and with way more power than my lil 355 tuned porc! i have a 400 pontiac and its a monster,and the cam is doin fine so far,and im not easy on that bandit either,does it have something to do with the fact that its tpi? cause my other older 355 was built the same but with holly carb set up,,i would shift it at 6500 ,and beat the **** out of it,and it would just not die!no roller,todays oil

 

No they arent in trouble if you use the right oil. Special order some flat tappet approved oil.

Its the general trend that alot of todays oil do not have the recommended amounts of zinc and phosphates in the oil that provide the lubrication necessary for flat tappets since almost all cars made today are rollers. To be safe, its best to run oils more suitable for flat tappets. Just a recommendation.

Rollers are just so smooth in operation and require no break in so they have their perks.

 

but it would be overkill to change everything just for that right? might as well put some good oil.

 

Yeah probably alittle overkill but smoother roller operation with abit more aggressive lobes tends to make more power overall. More valve lift area with steeper ramp cams, so motor should breath abit better. General trend.

 

ok lets say im willing to spend more money on this for the roller cam,do i go with the XR270 or the XR276? with the afr 195 and the big mouth base?

 

ok ,i just checked comp cams website, these xr270 and 276 are 738$ with the lifters,, but i found the roller retrofit ones,designed especially for my application,pre 86 motor,, and for fi,, the 260,268,280 and 292 xfi h13 cam and lifter kits,for 214$!!! is that good? please tell me yes, i mean its roller,retrofit for old block,especially for fuel injection,,,cant see a reason why it wouldnt be good.. so if it is, do i choose the 268,280 or 292? from what they say,feeels like id need 280 or 292,,,,at 214$ ill go roller for sure,,at 738 ,it would really turn me off,dont know why there is such a big difference in price

 

never mind the cheap ones are in the roller retro fit section and with roller lifter pics but when you dig a bit in the description,they are flat tappet,this is frustrating

 

the hell with it, ill keep my cam,pretty sure its not that big of a deal,for a motor that wont even run higher that 5500 rpm,cant immagine it will break the cam that easy,

 

hey guys,about the afr heads,do i take 65 or 75 cc chambers? i have high compression mahle pistons with 10.1 compression

 

The 10:1 rating is with 64cc combustion chambers. Sorry I didn't catch your earlier posts. I would have to say there is no way that a retro roller cam with lifters could possibly sell for $214. Especially not Comp Cams. Without looking for myself, I can't tell you what that is about. $734 sounds more like it. If you're using a flat tappet, just be sure to follow the break in instructions carefully. And do not run it on anything but either special flat tappet oil(high ZDDP content) or a common oil with a ZDDP additive. The money you are saving now on not buying the $734 cam, you will feel every time you drive the car. The idle quality and power output you get with the flat tappet would just be that much better with a hyd roller.

I know I'm being a little mean but I know this from experience. We build an engine using what we have even though we know we could do better if we just go a little further. Then, every time we drive the car we feel it. Ive built a few flat tappet motors for NASCAR where class rules required them. Of course because these were race motors, they also ran 12:1 compression which gives alot of grace with cam overlap.
Still, the same motor with a roller cam, and even with reduced compression for pump gas will outrun the flat tappet motor hands down. I know because I have one in my car now.

 

no youre not mean,your just honest in your advice,its good to know that i should consider buyin it at 734$ instead of spending 734 in special oil down the road,it ust makes sense.im strongly considering it,i still have to buy the heads wich are gonna be like 1400 plus better starter alternator waterpump,wiring,ignition system,so.... i have the choice here to just go cheap and drop in the good ol 305 tpi al painted and clean but stock,and finish the car for free,or have fun,take the 355 with the fat tpi set up,with good heads,,,might as well go all the way if im taking that route,halfway wouldnt make sense,so i better change the cam now,the one i have now,ill probly get 100 bucks back since its brand new.thanks for your advice,so heads,,65 chamber that i need on the afr? would give me lil less than 10.1,that ok for pump gas?with my set up,,i think aluminum heads have a lil more give for that too right?or is it the opposite?

 

Aluminum transfers heat faster than cast iron which means less thermal efficiency, which is actually a bad thing, but when we talk about pushing compression ratio to 10:1 on 92 octane, the aluminum's heat transfer becomes a positive. Plus, aluminum is easier to work with for porting and later repairs. So yes, go with aluminum and 65cc.

The final CR of your engine will depend on the actual compression height of your pistons. This depends on several things, from the machining of the main journals to how much the block was decked. Then, it is affected by the thickness of the head gasket you use. The standard Felpro Permatorque gasket is .034 compressed. There are thinner choices available but how well they seal over time, I don't know so much. Add gasket thickness to the distance between the piston top and the block deck at TDC and use a CR calculator, which is available on Summit Racing.com for free.

You are on the right track not to go halfway on this engine. It only costs us in the long run.