tourville

iTrader: (2)

I have an 87 L98(Rebuilt by Jasper) 350TPI 5.7L Engine froman 87 GTA, I converted over to the 1991 Speed Density harness and it isin my 1991 Camaro RS. The engine has about 15k miles on a rebuild and sodoes the transmission(automatic). The car is a street driven car, not adaily driver, it is more of a summer/weekend car. The current mods onthe engine are 58mm holley throttle body, slp runners, holley adjustableafpr, accel intake base(not sure about the model #), k&n on the throttlebody. Hedman headers 1 5/8ths with 3" catback flowmaster exhaust. Thetransmission is automatic with a shift kit and i believe a high revtorque converter. Im looking to change my cam. I have been told I shouldchange the heads and cam together. My question to you is what do yourecommend for a cam for me? And what do I need to change to accommodatethe cam? Also as far as tuning goes.. I have the equipment to tune, and am learning as I go, and also have a couple club members that may be able to help me out.

Im not 100% sure on the current hp that the car is pushing but i wouldlike to get the engine at 300 if not more than 300 hp. The following arethe specs on a stock 87 350... L98 V8 | Compression Ratio 9:3:1 |5.7L(350TPI) | HP 225@4400 | Torque 330@2800

here is my first sugguestion that I have gotten from tpiparts.net

Changing heads is not 100% necessary, but the improved flow of anaftermarket head will complement a more aggressive cam nicely. Assumingthis is a hydraulic flat tappet block, I would suggest something similarto this cam...http://store.summitracing.com/partde...4&autoview=sku

It has good street manners, noticeable change in idle, pulls goodvacuum, and will make a noticeable improvement in power. Assumingeverything else is in good mechanical condition and the engine isproperly tuned, it should not have a problem making over 300 flywheelHP. The powerband of the cam complements the TPI intake's powerbandnicely as well.

Whenever you change from a stock to aftermarket cam, you will need tocontact the cam manufacturer and find out what springs are needed foryour chosen cam. The stock springs are not stiff enough for anaftermarket cam profile. Keep I mind that if you order new heads, thesprings on the heads may be fine for your use, or they may not be. Itdepends what springs come with the heads. Also, if you keep the stockheads, the heads may need to be machined to accommodate the new springs,as very often the required spring stiffness is only available in a widerthan stock spring.

You might be able to run that cam on a stock tune, but I would recommendyou find a shop that can put together a custom tune for you (custom fueland spark tables). The engine will not perform to its full potentialwithout a custom tune.

One last thing to note is injector size. If you will be making 300 HP,you should consider a little bit larger injector than the stock 22 lbinjectors. 24 lb injectors will be a good choice, but keep in mind thatwhenever you change injector size, the injector size needs to be adjustinside the prom as well. This can be done as part of the custom tunepreviously mentioned.

customblackbird

iTrader: (15)

lol ok here we go!

first off, IDK WAT THE HE@L tpiparts is talking about bc that cam is a hydraulic flat tappet.... and your car is a stock hydraulic ROLLER cam, u should use hydraulic roller cams. that cam on stock L98 heads will not give u over 300hp unless u really port the stock heads alot. the heads will hold u back

the smartest thing i ever heard was.... "put a good cam on crappy heads and u got crap, put good heads on a crappy cam and u got more power!" not sure if thats how it goes but its the jist.

your intake is considered an aftermarket high flow TPI setup, if the plenum is ported to the SLP runners etc. your 58mm TB is way to big for your setup, a 52mm TB would help with intake velocity and give u better throttle response, 58mm TB are good for over 500hp larger 383's or larger where more air is needed. you have a good exhaust for a mild 350 so you really only have to do the heads and cam.

your stock heads are the same as mine on my 87 formula 350, they are poop! unless u port and polish the poop outa them they dont flow enough for the stock cam, even ported they arent as good as some cheap vortecs.vortec heads on a stock 87 TPI 350 increased 50hp with stock cam! dont bother with spring upgrades they are wasted money that could be put toward cheap aftermarket heads that can already handle the lift.
that is a tiny tiny cam, the duration is ok but the lifts are really low, they would work with stock heads bc of the lift being under .480. but if your doing the cam then i would do the heads, and the other way around, u will get more outa the entire combo by doing them both. most likely your heads will need a spring upgrade if being rebuilt anyways and machined for screw in studs. also the stock 22lb injectors can handle 300-350hp, u'll just have to bump fuel pressure alot, like 50psi. altho what im gona tell u to do 24# injectors are a better choice.

setup 1. cheapest

GM hot cam(218/228 duration, .525/.525 lift with 1.6rr)/modified lift vortec heads/1.6 roller rockers.... with your current setup u will see 355hp+/423tq+ (vortec heads require vortec manifold, sold under scoggin dickey) u could sell yours and pick up the cost.
cost 900-1000$

setup 2.

give comp cams a call
and pic a set of 170-180cc good flowing heads, vortecs, AFR, trick flow, patriot yadda yadda and tell comp cams so they can match the cam. expect 350 or more hp probably.

setup 3.

give TPIS a call, ZZ9 cam or ZZ409 cam, and 180cc heads good flowing and u can expect good HP numbers.


the hardest thing is your intake really, it will flow to about 5200 give or take so ur gona need a low duration cam with some good lift numbers, this will ultimitly decrease ur max HP numbers, and another intake like the HSR/superram/miniram. they will flow more air and expect alot more HP over the TPI. your setup now will max u around 350-400hp bc of the exhaust/intake. unless u start porting like WOAH!

a custom tune will def be neccessart bc yours is a SD and not a MAF. SD's have to be tuned perfectly or they run like poop. fuel and spark tables will need to be altered

tourville

iTrader: (2)

The mods on the engine came with the engine when i purchased it. Thats why it has a 58mm throttle body. My goal is to be over 300 hp.. if I hit 350 That would be awesome.. As far as spending money I have around 1000$ for sure that I am willing to spend and maybe a little more. But according to what your first "cheapest" setup was... looks like I could do something with 1000 or a little bit more. Im not really looking to hit 400 or go any higher. I think 300-350 is respectable and is more in my cost range =D. Everyone keeps saying to do the heads and the cam.. also change the springs/rockers. So most likly I will be doing it all at once and just do it the right way. Even if I have to spend a little bit more. Thanks for your input! lots of good info there

customblackbird

iTrader: (15)

i know what u mean but for the same price as doing the springs on the stock heads and having them rebuild basically with all the machining u could basically pay for almost a new set of heads.

the 58mm TB isnt bad its just gona hinder throttle response bc its gona sloow the velicity of the air which is why the TPI makes so much torque. there will be a million ppl on this site that will flat out trade u a really nice BBK or holley 52mm TB for your 58mm holley TB. so that wont cost u anything.

cheapest would be to just throw on scoggin dickeys modified vortec heads... i think they where 330-360 a head assembled. so figure 700$ for those heads, and scoggin dickeys vortec base is 400$ but if u sell ur intake u could make up sum or most of it. so figure 200$ for the base. thats 900$ and u got almost 300hp with just those 2 mods, the runners/TB/plenum porting/50psi fuel pressure (stock injectors) and u got another 25hp so figure 900$ and ur at over 300hp. that would be the cheapest.

this is what i would do, it would be the 2nd cheapest but best bang for ur buck. do the same above but i would def do a cam change, u have to match the cam to the motor/intake etc. u can easily pick up 30+hp with a simple cam swap. since ur gona be peaking at 5200 roughly maybe alil more if u work the intake and slp runners a smidge. your cam prob shouldnt have duration over 220 degrees at .050. but u want ur lift in the high .4 to low .5's this where where the vortecs peak in flow. the GM hot cam is a nice cam, 218/228 .525/.525 with 1.6rr and its cheap at 200$ scoggin dickey. but its a rever and pull to about 6000rpms. so ur intake would restrict u alil. give comp cams a call there the only ones i trust personally... they kknow wat there talking about. they could set u up. i would figure 900$ from before and 200-250$ for the cam. u can reuse ur roller lifters and then depending on the lift of the cam u could get 1.6rr for more lift and more hp....15hp usual increase for added lift. i got nice extruded aluminum 1.6 full roller rockers from proform for 160$ i think.

id say roughly 1200-1400 depending on what u do or decide to go wit but u'll be somewhere around 350-375hp.

joeblue83

iTrader: (8)

I agree with the TB size is way to big. The 52mm throttle body pushes 900 cfm. Each horse you make you need 1.5 cfm to feed it. So unless your pushing 675 horse you dont need a 58mm. A 52mm will still be on the big side but will be much better. A good combo that i had was a aluminum set of edelbrock heads with a zz9 camshaft from tpis. You can use the stock springs with this combo. The nice thing when i had this combo it yielded 17 mpg and put out 290 rwhp. Worked out very nice. Any questions just let me know, i went through the same as you did a few years ago

tourville

iTrader: (2)

1200-1400 seems okay to me to spend.. to get 350 hp?! do you have any links to those parts you were talking about?

joeblue83

iTrader: (8)

TPIS.com

RPOL98

with all the mods you already got on the motor (intake, exhaust side), your next step is the heads. IMHO, if you put a cam in, and don't do the heads, you're probably wasting your money, although you'll probably get that sexy rumpity-rump idle for stop-light image and drive-in credibility. but you won't be able to get the improved breathing benefit of the cam.

so you gotta do the heads, even if it's el cheapo cast iron hi-perf heads.

of course, if you're at the point where you're pulling off the heads, then it doesn't make sense to not do the cam while you're at it.

I went with the GM LT4 HOT cam, with 1.5 RR (not 1.6) for better street manners. it was based on cost, when I bought that cam, the cam by itself was about $170, reused my factory hyd roller lifters no problem. I don't think you can get a decent hyd roller cam for anywhere near that. I think GM now has a couple more choices though..

just my 2 cents. good luck!

Orr89RocZ

iTrader: (20)

i agree with the above, you got some good mods as it is. stock L98 camshaft with 1.6 rockers will support 300 flywheel hp. i'm sitting on 254 rwhp with my hsr L98 and probly have 260 in it. Thru an auto thats about 300 flywheel hp as it is. a simple cam swap could give me 40-50 hp more. But a good set of heads like AFR 180's will also make some good power on stock cam.

Your car with those mods should dyno in the 240ish whp range with a good tune and assuming its all port matched. thats probly closer to 280-290 flywheel. my buddy had slp runners/aftermarket base for mods and he made 250whp he said which was probly rounded up from a high 240 value. lol

any SMALL cam added to that current motor will make good power. i can see 275-280whp which is 330-340ish crank/flywheel. ZZ9 is a good overall cam but i wouldnt use stock springs..it has way too much lift for stock heads as they sit as is. you need to shim up the springs or get the guide bosses ground down. also i'd recommend screw in rocker studs. i was hoping to add a cc503 cam 224/230 .503/.510 to my L98 on stock heads with just abit of porting/polishing. hoping for 300whp or 350-360 flywheel hp atleast.

customblackbird

iTrader: (15)

SDPC2000.com i believe is scoggin dickey
TPIS.com
compcams.com i believe

ok for get about the stock heads completly.... there not worth anything but make a good paper weight or a nice dumbel for curling.

overall the hotcam is a nice cam cheapest ive seen, i had one and i got it for 190$ prices have gone up... but i sent it back for a compcams XFI280.
dont do the cam if anything do a head upgrade but to take advantage of the heads do the cam as well. if u get a hydraulic roller u can reuse the factory lifters. either way get the heads so there springs can handle higher lift like to the .525-.50 range.

tourville

iTrader: (2)

i have decided i will do both the heads and the cam. i have a garage to use now and have the whole winter! and would like to get started in early december. So with that in mind... guess i need to get a little more serious and start finding the heads i need and a cam to go alogn with it and whatever else taht should be changed. i do not want to half *** this might as well do it right the first time. Looking to get anything over 300hp to the rear wheels. 350 would be great and would be very happy with that. So my best bet is to go with the vortec setup? or something else? and a gm hot cam? with 1.6 roller rockers? or 1.5? and ill get whatever springs etc that the cam company sugguests.

Orr89RocZ

iTrader: (20)

well if you want 300 at the wheels or more you'll need a bigger camshaft for sure and decent heads to go with.

scoggin dickey sells a vortec hotcammed crate motor that is advertised at 357 crank hp and thats with untouched vortec heads and edelbrock highflow system which doesnt flow all that well compared to big tubes from TPIS/AS&M. that motor is capable of putting down close to 300 at the wheels. You could do vortec heads/vortec base and hotcam for fairly cheap if you shop around and get stuff used but in good condition. You'll need good exhaust and tuning tho

if at all possible, look to get TPIS/AS&M siamesed big tube runners. that will really help your goal and give you a bit of breathing room up top. you can get pretty much any good aftermarket aluminum head like trickflow/afr/dart/brodix in the 180-195cc intake runner size. those will flow plenty to make over 300whp even with fairly mild cams.

AFR/Trickflow/Canfield 195's and XFI268 cam will rock out power under a TPI system but its a much more costly route

3rdgenZ

iTrader: (1)

with the money you have at hand.. I'd get some edlbrock rpm heads and the hot cam kit. ive seen a 3rdgen vette go 13.0 with the slp,edlbrock heads and hotcam. the vortec swap can be costly, not to mention you would need a new base.

http://store.summitracing.com/partde...2&autoview=sku

http://store.summitracing.com/partde...5&autoview=sku

you could just buy the cam and rockers, and save money. i just dont know how good edelbrock's valve train is.
sorry if this has been said already

customblackbird

iTrader: (15)

TPIS/AS&M runners are pretty $$$$! since u got the SLP's dont worry about that, u will have to port match everything with the SLP's to get full advantage of there design... this is to save some $. if u want to keep the base you could, the accels arent bad there basically the edelbrocks base... actually i think now when u order and accel base they send u an edelbrock in an accel box lol. port the plenum nicely, to fit the SLPs , clean up the SLPs if u want and port the base slightly and u got a good flowing intake.

by keeping the accel base u can save money, and could put more towards the head/cam. i would look into a 180cc head for your tpi system since u will be peaking around 52-5500 with the TPI. 195cc is a big head and should be used with a higher reving intake/larger displacement engine. look for some 180cc heads in your price range. Patriot/AFR($$)/trickflow/dart/edelbrocks are nice etc i would be looking to pay 800-1000 for the heads if u get a nice set maybe even aluminum . the heads should be able to accomodate up to .550 lift with a ROLLER CAM!!!hot cam is .525/.525 with 1.6rr. make sure u ask that! it has to be for a roller cam since they need larger higher lift springs than flat tappets. most aftermarket heads will take that lift no problem. then look into a good cam. the hot cam is a nice choice and is an upgrade for LT4s and in the package with the LT4 motor the hot cam makes 450hp so its more than adequate and will give u good vacume/idle/throttle response. , then look at 1.6rr and you will prob have to get self aligning rockers... unless they heads use guidplates then u will have to get hardened pushrods.

also make sure when u get the heads that they are screw in studs/ have the lift of .550 at least and if they need longer/shorter pushrods for your motor...

with a good set of 180cc heads/hotcam/1.6rr/ slightly ported intake/custom chip i think u will be pushing upwards to 400hp. which will give u more than 300whp. this can be done for 1400 without a doubt.
1000 for heads
200 for cam
170 for 1.6rr
and your done

Orr89RocZ

iTrader: (20)

siamese the slp's

and dont forget the cost of new gaskets and stuff. then the tuning...

RPOL98

SLP runners are already siamesed at the plenum side. I guess that some folks increase the siamesing to increase the upper plenum volume, and shorten the individual runner (IR) length, in pursuit of prospective upper RPM HP gains.

port-match, cut/grind the upper plenum side openings to match the SLP runner entrances.

at the lower side, I myself wouldn't siamese the SLP runner outlets at the manifold base.

customblackbird

iTrader: (15)

yea i second that.... up at the plenum is fine unless u wanna siamese it alil more from the top, but u want to keep the overall individual runner.... this is what gives the TPI is insane torque... and driving on the street is always more fun with lots of torque

porting the runners or extrude honing them to make them larger will help, and then i would do the same... u want to increase the inner diametere or the tubes if ur gona do anything to the runner and base

Orr89RocZ

iTrader: (20)

i'd siamese abit more... you wont loose all that much torque. i still have 315lbft at the wheels from 3100-3300 and over 300 to 4000rpms in my short runner HSR. TPI dies off well before 4000 rpms in the tq department

SLP_GTA

iTrader: (1)

here is a link for SD tuning if you don't do your own. http://www.scotthansen.net/

tourville

iTrader: (2)

alright tomorrow im calling about patriot performance FREEDOM Series heads(alum) to see if they clear GM hot cam specs 218/228 .525/.525 lift.... and go from there. thank you everyone for your help.. and ill continue to post up anything new... and if anyone has any input feel free to keep on goin!