scarly10

I'm going to be upgrading the cam and heads (possibly valve springs) on an 87 Iroc Z with a 5.7 350. I have done headers, exhaust, slicks, but no other motor changes. What cam and heads have been successful for you? Looking for something fairly budget friendly. Please share! Thanks!

Night rider327

iTrader: (13)

What does "budget friendly" mean to you?

Are you keeping the TPI? Stock intake/runners or aftermarket? Or are you going with a carb?

The stock 96-02 L31 vortec 350 truck heads are great budget upgrade heads, but will need valve springs, some sort of mod for higher lift limits, and vortec intake.

I like the Brodix IK heads and pro filer heads for a "budget" good flowing alum. head. They are in the $1,000-1,300 range.

I will not recommend a cam as of yet, cause it needs to match the heads you use.

scarly10

I think the $1,000 to $1,300 range is about where I'd be for heads. I'm leaving the TPI as is for now. It's stock. I have thought about just doing a cam upgrade for this season and leaving the heads stock as well. Just looking for different options and ideas.

Orr89RocZ

iTrader: (20)

Really wont gain full potential of cam and heads with stock tpi. Will need that upgraded eventually.

Love the afr line. The 195's work great! Work well with lunati voodoo grinds and comps xfi grinds as well. Short runner intake like stealth ram or single plane for efi

83 Crossfire TA

iTrader: (2)

If you're staying with the stock TPI, the question is if you want to cam for that or for whatever you plan to upgrade that with (If you plan to)? What you would choose as a cam would be significantly different.

WRT to heads I'd do the best deal you can find on heads in that range... I'd probably shop around for some used ones like the mentioned AFRs (I haven't checked pricing on them but I don't believe that you'll get them assembled in that range), but most heads will flow enough for you to have good luck. If it was me I'd be looking for some 64cc or smaller chambered aluminum heads (mid/high 50s would be better) with intake runners under 200cc. I don't believe that there are many in that price range assembled that will bolt right up _correctly_ (a lot of the cheaper aluminum heads that flow well use taller/narrower ports and may technically bolt up but not be a great fit without some work) but I could be wrong, I haven't been keeping up with the cheaper import heads out there for the last couple of years. The only ones that I can think of that will and that match everything that I listed and in your price range are the TFS 23* heads.

I just needed a set of heads with similar constraints but for a 305 and I ended up taking a set of LT1 heads, welding up the coolant passages/relocating them, same with the intake manifold flange, and porting them and installing some nice stainless valves, some PAC behives (rated for .650" lift)... It basically cost me parts + my labor, but I'd bet that you'd be at around $1000 paying for parts + labor and have a better set of heads than the TFS heads but much more of a PITA even if you know what you're doing.

scarly10

I found some used LT1 D Port Aluminum Heads today. Here's what was listed: Heads have...
• 58cc Chambers
• 163cc Intake Volume
• Screw in Studs
• Pushrod Guid Plates
• Springs for flat tappet cam
• Manley Stainless Valves
• Mild Port and Polish
• Gasket matched to a FelPro 1205 intake gasket
• Positive Valve Seals

would they be something I could make work? He's asking $500 for the pair.

thomas1976

Would probably be easier to go with a set of 170 summit racing heads https://www.thirdgen.org/forums/tech...ml#post4577237 then the LT1 heads you found.

Thirdgen89GTA

iTrader: (5)

I think you should plan your entire build out. Take a look at how much power you want to make and see if TPI will get you there.

With a stock intake on top, upgraded heads/cam will only get you a poorly running car that is about as fast or slower than a stock car. You'll need a Tune right away. I would suggest looking at aftermarket intakes and upgrades. There are a few paths open to you.

A fully upgraded TPI car with all of the bolt-ons is a pretty fun ride and will require minimum re-tuning of the ECU. You could easily have a mid or low 13 second ride without impacting your tune significantly.

Once you have all of the external goodies you can look at heads/cam.

If buying a as cast piece, I would go with either a FIRST TPI, SuperRam, Stealth Ram, or Mini-Ram. First and SuperRam will provide similar powerband as your existing TPI. HSR and MiniRam will shift your powerband to something more like an LT1. Very flat torque curve with the last two intakes.

Upgrading the stock TPI can be done, but basically gets to be as expensive as purchasing a FIRST TPI or SuperRam. A SuperRam can be done in stages, its compatible with the aftermarket TPI bases. A First TPI is not compatible with any aftermarket OEM style TPI parts.

Night rider327

iTrader: (13)

I agree with a lot of the others above.

Buying the $1,000-1300 brodix heads or $1600 AFR heads and keeping the stock TPI is just shooting your self in the foot and throwing money away.

The intake is just too much of a limiting factor. It does not flow very well, it's "tuned" to made low and mid range power, where those better heads and the supporting cam will like to be wound out to atleast 6000 rpm.

That intake is pretty much done by 4500 rpm.

Step back and look at your 1, 2 and 3 year goals for the car.

Again IMHO not even worth spending the money on a cam now to match that intake if your plan is to change it in a year.

83 crossfire made a great point too. Those better heads will not seal to the stock TPI intake. I run the brodix IK 200 heads and it just barley seals to an edelbrock performer RPM intake.

project89

iTrader: (1)

assualt 200cc aluminum heads( 400 shipped pair bare) , and hsr clone 250$ with fuel rails

have that on my engine with a small cam, setup for turbocharging , even with the low compression tiny cam , and manifolds more restrictive then the stockers ( turbos removed from log manifolds) it makes a ton of power

project89

iTrader: (1)

https://www.thirdgen.org/forums/afte...00cc-64cc.html

83 Crossfire TA

iTrader: (2)

I've done it, but I wouldn't recommend it to someone that doesn't know what they're getting into or at least has someone that does to do the work. At the very least you'll need to have the decks welded and decked, and then either the same for the intake flange or drill the intake manifold to match the LT1 pattern. Then you need to figure out how you're going to run a coolant crossover.

I don't understand why everyone says that they gasket matched them to a 1205 fel pro, since stock they have different bolt patterns, it's not like you're going to use a 1205 with them so why do it, and the stock GM LT1 gaskets are as large, but with slightly different dimensions so it makes even less sense.

oh, and while I'm at it why the heck would someone put springs for a flat tappet cam in a set of LT1 heads???

He probably has more than that in the if all the work was done well... Is it worth it, well if you can get the rest of the work done for not a ton, then it would depend on what the flow numbers he got out of them are.

Past that figure that you'll probably have to junk the springs/retainers and replace them with something appropriate for whatever roller cam you're planning on running... figure that into the cost.

OK, all of you are making a bigger deal of the problem the TPI intake is.

A STOCK L98 car is a mid 13 second car (well tuned and with a good driver, my '87 formula 350 ran 13.5@100 with an old SLP cold air and cat back on STOCK 16y/o(at the time) goodyear gatorback tires. With a torque converter, better tires and maybe headers it would have been a 12 second car without pulling a valve cover or the intake (I never got a chance to try to go faster with that combination since the transmission was sketchy when I bought it and I blew it up).

Yes, it is easier to go fast swapping the stock TPI parts out or going with a different manifold, but the stock TPI will flow enough air to feed 400hp with a minor clean up, but you have to run _very_ well matched parts to get anywhere near there.

Answer my questions from my first response about the intake and cam and maybe we can figure out where to go.

DIGGLER

iTrader: (1)

my LT1 had some 1205's on it. the bolt pattern is the same as a sbc, just at a different angle. 1205's will work fine with no modifications.

what makes a spring "flat tappet"? if you were running a flat tappet cam with lt1 heads, why would you not run "flat tappet" springs?

that is a pretty awesome timeslip for a tpi car. what was your 60'? i remember my stock LS1 car went 13.28@105ish with a 1.9x 60'. manual trans.

if you want to keep it "retro", i would keep the tpi and set it up to make as much torque as you can down low. because the intake will choke at 4500. im thinking lots of compression, awesome heads, and low-ish rpm hydro roller cam. (as much dynamic compression as you dare) i would get some 185 heads cnc ported by spier or somewhere like that. save up for heads and skimp in other areas.

if you dont care about the retro thing, i would ditch the tpi intake immediately and run something that will let you scoot your hp peak over to the right a thousand rpms or more.

Orr89RocZ

iTrader: (20)

My car has seen 13.8's at 100 on street tire when it was headers/catback L98 with stock tpi. 3.27 gr. went 3.42 and lost 2-3 mph for some reason but ran 13.6 at 97 on et streets.
Stealth ram and minor other bolt ons i got down to 12.95 at 104

Thirdgen89GTA

iTrader: (5)

By fully upgraded TPI I mean all the bolt-ons, stock long block. Stock heads, cam, and short block on street tires. No other drivetrain mods like slicks, stall....etc...

With good cam/heads? If you can't get out of the 13's you got problems.

Orr89RocZ

iTrader: (20)

Stock shortblock L98 with afr 195's and a 280xfi cam is high 11's all day long with 3600-4000 stall.

Todays heads and cam tech makes achieving near 400 whp easy and thats mid high 11's in most stock weights

83 Crossfire TA

iTrader: (2)

huh, you either had an interesting LT1 or weird 1205's... or maybe I wasted a bunch of time welding and machining the LT1 flange to work (for that matter why did the LT1 manifold swap guys all have to fill and redrill their inside holes?)...

The felpro gasket in this pic is a 1205 and the black gasket is a gm factory LT1 (you can see the stamped labels in the pic). Yes, the outer bolt holes are in the same location and at a different angle, but the 4 inside ones are in different locations:


For that matter, you can see I cut the top off the 1205 also because it doesn't clear the stock LT1 valve cover rail either (I ended up cutting the rails back when I re-machined the intake flange surface so I can use an unmodified 1205).

That pic also shows how close the stock LT1 gaskets are to a 1205, something else I mentioned in my original post, it doesn't really make sense to port to a 1205 if they are intended to be used on an LT1

Nothing except for some monkey called them that in their ad and that's what's being discussed in this thread. Since typically flat tappet cams have less lift and the lifters are lighter you can assume that the springs will tolerate a lower total lift and they have a softer rate than something intended for a roller cam, and therefor insufficient for anything he'd want to run in his stock roller engine, which is why I said they'd have to be replaced.

Because an LT1 never came with a flat tappet cam, and I don't even know that you can get a flat tappet blank that will fit an LT1 block (with the right snout...)

the only other explanation that I can come up with is that this is possibly a set of early 70s iron SBC LT1 heads, but that doesn't explain your response DIGGLER, because then you would be running the right gaskets for the application and there wouldn't be any bolt angle differences unless you were bolting a late model manifold to them (like a TPI).

It's nothing special... I had a slipping trans that let go before I really ran good times with the car. like I said, I bought the car with some _original_ 245/50-16 eagle gatorbacks (the guy I bought the car from bought the car new, took half of the original stuff off of it and threw it in the attic and raced the car in f-stock autox), I think I ran a best of a high 1.8x 60 on those and they were hard as rocks, had to burn them good to get any traction... That setup had easy 12's in it without opening the engine if the transmission didn't let go (and someone hit the car in a parking lot hard enough to total it so it became a parts car)

My '97 LT1 WS6/T56 car ran a best of 13.001@107, with literally nothing done to it but gears and a hypertech tuner to raise the rev limiter/adjust the speedo...

Yea, my crossfire car and another TPI car, both 3.23/3.27 cars both went slower with 3.42 gears... not surprising.

I just ran 13.6@100 in my '87 305TPI/M5 car at the fall MM event, with nothing done to it besides headers, exhaust, gears (I had a 9" sitting around with 3.50 gears that work better for what I will do with the car eventually so I swapped that in, the better gear helped but I'm sure the extra 100# the 9" added hurt) and ET drags, and I expect just a intake manifold swap to put that car into the high 12's, so I agree with Thirdgen89GTA, if you can't get 45cubic inches more out of the 13's with a cam and heads you're really doing something wrong.

280xfi... with a TPI or with a swapped intake? I love that cam but it's a stout cam for a stock TPI intake.

DIGGLER

iTrader: (1)

83, on the heads, i believe i was mixed up. my LT1 exhaust ports were matched to a 1406 and for some reason i was thinking intake gaskets..... and i ran a single plane on it where i modified the bolt holes, but i didnt remember having to move them. -but it looks like i did.

flat tappet stuff- he was talking about modifying lt1 heads to put them on his sbc. thats why i said if he was running a flat tappet cam he should run the associated springs for it.

Orr89RocZ

iTrader: (20)

280 xfi plus afr heads plus intake...hsr was used on the build i tuned but a miniram or a single plane would work

kevins88

please help mw.....ive got an lt1 short block ive placed all of the tpi stuff on ,now i got oil coming out of the passenger side waterpump ports where did i go wrong and how to fix it

Thirdgen89GTA

iTrader: (5)

WuT?

Make new thread.

RustyFormula

iTrader: (1)

Great discussion, guys! Just wanted to say thanks for the info. This will be a big help in upgrading my L98 when the time comes.