TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Hello TGO members, Ive been strolling the site for a while now and im about to dive into my car this winter. I have read mixed emotions about the lb9 motor getting a lt4 hot cam. I have a 88 lb9 5 speed. Can I do the lt4 hc swap or not? Ive seen post about yes and no anwsers. I plan on a set of worl 305 heads and a intake of some sort after the heads and cam. I already have headers and exhaust, K&N drop in, underdrive pullies and a tpis air foil. I can get the lt4 cam real cheap if i get a response soon. Also would I be better off with 1.5 or 1.6 roller rockers? Any information will be appreciated.
I'm far from an expert but a hotcam always seemed like a little too much duration for a 305 with TPI. Lift with 1.5 rockers should be OK. For a genuine GM cam, (inexpensive roller), I'd think a ZZ4 would be about as far as you'd want to go on an LB9. Just my 2 cents.
BTW, its funny around here. Sometimes you'll get 20 replies and sometimes you're ignored like you got the clap.
__________________ 08 Kia Rondo 2.7 Auto.
04 Sierra 4.3 Auto.
92 T/A 'vert 5.8 Auto.
86 Fleetwood d'Elegance 4.1 Auto.
No crap about the clap thing,lol. But I was thinking about the zz4 cam. Can I use the 1.6 rockers with it and get away with that? What kind of gains could be expected with that cam and world heads?
That would put you well over .500 lift especially on the exhaust side, so make sure you check piston/valve clearance. I've got to believe that would be worth at least 40-50 HP with a proper tune.
__________________ 08 Kia Rondo 2.7 Auto.
04 Sierra 4.3 Auto.
92 T/A 'vert 5.8 Auto.
86 Fleetwood d'Elegance 4.1 Auto.
zanesville ohio, hell were almost neighbors, i live in newark ohio ,i'd stray away from the hot cam, the xr256 wouldn't be a terrible choice, i have a crane 2032 .452/.465 214/220 duration at .50 112 lsa, going in mine over the winter. personally i wouldn't go any bigger than that crane cam with stock heads and intake, all you will be doing is losing power under the curve.
i have pocket ported 187s going on mine, siamesed intake manifold and bigger injectors and i still don't expect it to be what i would consider a 100% matched combo.
if you're looking for a set of heads, i've got a set of 85% ported 416 casting heads in the garage that i'd let go of pretty cheap. Came off an 86 iroc-z with 39k miles. Was planning on putting them on mine ,but i don't feel like buying new valve covers and redrilling the intake and all that bs.
as for a tune, well if you have maf you wont be to bad off...... i personally plan to run mine untuned and tweak the fuel pressure and timing at first, i can dyno mine at c-tec and get afr read outs. to see how far off i really am.
Thats bad *** That your that close. I used to live in newark. Now I live outside of Glenfold on route 668. I went to the c-tec in zanesville and graduated in 07. Do you ever go to the Trails? Ill give that cam a look. How cheap is cheap on those heads you have got? What all needs done to them?
Wow, never thought I would see "Zanesville, OH" come up on here. I was born and raised in z-ville. Graduated from West Muskingum in 03 but live in NC now. More power to you with the cam swap but FYI the cam that you've got is the most aggressive one ever put in a third gen. It only came in LB9s that were mated to a t-5 in 88 and 89 only. This is the same cam that they put in the L98. You can definately pick up some power with a performance cam but whatever you do, don't throw your old cam away!
I think the hotcam would work better with siamesed type runners or stealth ram. its gonna pull to 6000 rpm where TPI does NOT shine, even on a 305. SLP runners will help that along with ported or aftermarket base.
I'd run 1.6 rockers only if your PTV clearance is good and the heads can flow to .500. They should tho.
Else, go abit smaller. Anything in the 212/218 duration range or similar would work well in a TPI 305. Factory L98 cam aint bad at all either with 1.6 rockers.
Like I said, because of the rare combo you have: 88 LB9 T-5, YOU ALREADY HAVE A STOCK L98 CAM. I agree with Orr89 that 1.6 rockers will significantly increase your valve lift and therefore make more power due to your already aggressive (relatively) cam profile. I've been thinking of throwing 1.6s on mine too. You need to make sure and get the narrow body kind if you decide to keep the stock heads though.
I'd swap to 1.6's first to see how you like it but it may need a tune to take full advantage. 10-15whp could be gained there and with other basic bolt ons you will increase power a good bit. If its not enough, then get a cam...you will already have the good rockers for it.
Holy crap man, I graduated from West Muskingum in 2007. My sister would have graduated a year before you. But it looks like ill be looking for some roller rockers to start me off. What is the best cheapest brand of roller rockers that I can buy? What would be a good mod to come next for me? I have headers, full exhaust, no cat, underdrive pullies, air foil, and K&N filter. I already have a 9 bolt with 3.42 gears. What do you guys think.
personally i'd say forget about rockers, i mean don't get me wrong they are a great upgrade for the money ,but far from the best bang for your buck.... Gasket set will run you about 80 bucks for a tpi top end, head bolts will run you 30$, after market used roller cams can be had for less than than 200$. I got mine for 100$. I paid 220$ for my rockers i expect i gained about 10 to 15 hp with my rockers max, i hope to gain at least 20-25 from the cam swap.... Just trying to put this in to prospective.
get yourself a used camshaft in the realms of what we were already talking about and you will be way ahead of the curve.
i already have everything you do plus 1.6 roller rockers and some dumb ignition stuff and such.... pretty much in same boat as you.... what i plan to do is install my crane 2032 , siamesed upper plenum, siamesed base and gasket match it to 187 heads. then i should be able to pull to an easy 5,500 rpm and still make good power.
thats crazy you graduated from c-tec in 07, so did i, it sure is a small world out their. My name is Gerry Lutz i'm sure i saw you around up there. i was in auto tech yourself?
oh btw as for the heads i'd let them go for 100$ if you want them, nothing is wrong with them, they need reassembled, finish ported, and i would probably have them hot tanked as they've have lots of surface rust from sitting in my shed for two years.
if you ever need a hand wrenching or advice let me know
Ok, im looking at cams agian now. Ill just do it all at once when I swap. I have the ignition stuff to you talked about and fully suspension mods. I hope that I can get this thing to turn a 13 second pass at the trails and ill be happy. I graduated from the c-tec in zanesville in the welding class. I work in Pataskala now.