Hello all, I've got a 1989 IROC-Z and seem to have either blown z head gasket or maybe piston rings, with the symptom being it's pouring coolant into the exhaust but not mixed in the oil.

Have always wanted to do a performance build so now would be the time, so what is the largest stroker I can make out of the stock block? Or would i be better off just doing a roller and swapping it?
Goal is 500-600 hp and 500 tq solidly throughout rpm range, want to be able to beat the new cars.

Notes: already have a built 700r4 supposed to handle 500 hp/tq
walboro 255lph pump
Adjustable fpr(southbay) 22lb b3 injectors(southbay)
Subframe connectors, full spohn tubular adjustable suspension minus torque arm, eibach springs lowered 1-1.5", adjustable struts all around, tubular a-arms

Any advice is greatly appreciated, thanks.

 

Coolant in exh but not oil = either cracked head or failed head gasket (more likely the former but still very possibly the latter)

Definitely NOT caused by piston rings

I'd recommend popping off the heads and seeing what the problem (ahem, the "opportunity for a solution") really is, and making a decision from there.

Note that I DID NOT say "your rings are good", "your engine is just fine except for this one problem", or ANYTHING ELSE of the kind. NOT NOT NOT NOT NOT NOT NOT NOT NOT. Please, no one put those words in my mouth. You still might have a problem with rings, we simply don't know that yet, and can't tell based on what you've told us so far. What I DID say is, nothing about piston rings can POSSIBLY exhibit itself in this symptom. The SPECIFIC symptom you asked about is caused by SOMETHING ELSE. One of the things you must always do as part of realistic troubleshooting is, eliminate all proposed "explanations" that CANNOT be right; that is, ones that don't fit the observed facts. See my signature.

You're not going to get 500 HP with that TPI on there, no matter how big of a stroker you build. The only way is about 200 HP of nitrous, or a SERIOUS centrifugal blower. Not sure what you're asking about "doing a roller"; that's largely meaningless, can't really speak to that. You're not going to realistically "beat new cars" with a traditional SBC regardless, at least not very often or for very long of a stretch between MAJOR repairs, if you're at the level of asking this type of question on the Internet. Yes, YYYUUUUUUUUUUUUUUJJJJJJJJJE power can be made with one; NO, it is not easy or cheeeeeeeep, and even very experienced people find it a struggle. Quite simply, you could spend YEARS of trial and error and budget-busting failure, and still not get there.

If y our goal is to "beat new cars", probably the cheeeepest eeeeeeziest most assured way of doing this, would be to replace your 350/700-R4 with a LS3/4L60E pullout, and use THAT as your platform for modifications, instead. It may sound like a major chunk of change, but until you've built a few motors and experienced disappointment, you have NO IDEA how much coin you can pour down the drain that way. The other will get you farther, quicker, cheeeper.

 

If you want that much power and driveability… LS

 

Yeah i myself thought it was probably the head gaskets or head but my neighbor said he thought it could be the rings, either way my point was it needs to come apart.

I am aware of the stock tpi airflow limitations and was already planning on swapping intakes.. leaning towards a FIRST fuel injection setup or maybe a super ram or similar, still doing more research there on what would best fit my applications.

Assuming that my block is okay, at the very least will be doing a 383 stroker.. have seen quite a few 383's in the 500+tq/ high 400 or low 500 hp range, just one example is on RCS racing website (may have spelled that wrong, name escaping me this very moment) which uses the 835 cfm FIRST intake and their own cnc'd heads on a 383, advertised at 460 hp and 520 ft/lb. So, it doesnt seem super hard to get a 383 to the levels i want with the right parts matching.

My thinking is maybe with the 1000 cfm intake and a different cam, better heads, etc. may be able to get to the 500 hp mark and even more or at least no less tq.
Or maybe the 1000 cfm would only work well on a 400+ cu.i , I've emailed them for more information to that regard.

An LS swap isn't out of the question either, I'm only considering sticking to sbc because I've got a nice built up 700r4 in the vehicle already, which I believe can be adapted to an ls however would probably be better off selling it and doing the 4l60e, i did have a friend with an lq4(?) 6.0 truck ls that he said he'd sell me for around 400$... supposedly was running but missing one thing it needs to be complete that was robbed for another engine, will have to see if he still has it. What i would need to know there is what exactly is needed to put an ls in a thirdgen.. and if it's a truck ls what needs to be changed besides accessories locations and oil pan..

Thanks again.

 

First and foremost:

LEAVE THE STOCK SHORT BLOCK ALONE.

If you don't HAVE TO take out the pistons, LEAVE THEM ALONE.

Your current motor is a pretty damn good, as old-skool SBCs go, as an old-skool SBC. It has decent compression, decent enough heads, and so on. FOR 1989.

Butt, NOW, it's 2021, almost 2022. You're in SOME WHOLE OTHER BALLPARK from 1989. Which, if I may be so bold to say, ANY TPI motor, was COMPLETELY OUTCLASSED by the competition, in 1989. In 20221, almost 2022, that problem (ahem... "opportunity for a solution") is EVEN GREATER.

The First intake will allow you to "beat" STOCK TPI motors. Might MAYBE allow you to COMPETE WITH, not necessarily BEAT, similar stock-ish motors of the same era (Mustangs), but certainly is no "guarantee". It MIGHT MAYBE extend the capabilities of an otherwise stock-ish TPI motor to 350, maybe even under the most optimistic, conditions.

Not going to get you to anything remotely grossly dimly vaguely anywhere near "beat the new cars".

Yeah it SUX. Yeah I HATE IT. Yeah IT'S a BEOTCH. Do ya wanna complain? do ya wanna P&M about "it's not fair"? (women can P&M at the same time: they have 2 sets of lips, one to P, and 1 to M) or do ya wanna WIN?

In 2021 (more likely 2022, before you actually DO anything, besides self-pleasuring), TURF the old SBC. If ya seriously wanna "beat the new cars", the old crap isn't gonna cut it. It's not like the whole human knowledge about ICEs has remained static for the last ... oh, say, .... 65 years. Like, since your GREAT GRANDPA was nothing but a gleam in your GREAT GRANDMA'S EYE as they rode in the horse-drawn car together. Knowledge has moved on. EMBRACE knowledge. It's A Good Thing.

 

So I just wanted to mention something, after reading all of this.

Old Engines, New Cars, Technology changing, Etc...
As far as SBC Engines go; the Gen-III/ Gen-IV Engines benefit immensely from Technology.

What am I talking about? ...what Technology?
Many things; and lots of different Technologies.
But I do not feel like typing a long complicated Post at the moment.

So, simply put; the Gen-III/ Gen-IV Cylinder Heads have significantly more power potential (as a result of modern Tecnology)...
Stock Gen-III/ Gen-IV Engines... or at least Stock Gen-III/ Gen-IV Cylinder Heads can go a long way in terms of power production.
I mean this in comparison to Stock Gen-I Engines.
Aftermarket Cylinder Heads will be required for a Gen-I Engine to have similar power production as a Gen-III/ Gen-IV Engine.

Can Gen-I Engines make as much power as a Gen-III/ Gen-IV Engine?
Yes! They can make over 2,000 HP! ...just completely without any stock Parts.

The Gen-III/ Gen-IV Engines will provide a much higher initial power potential (with all stock Parts).
The Gen-V power potential is even higher... but come with other issues, such as the Fuel System.

 

Completely agree, it seems that if i really want big power, reliably anyways, an ls swap is the way to go..
so, what would be needed to do so?

From what i currently know, I will need the following:
Ls swap Engine mounts
Adapter plates for engine mounts
Adapter flex plate to 700r4(since mine is built)
aftermarket efi control?(simpler to install?)
Tubular k member for ls swap
Likely Axle swap but may use stock till it quits
Ls compatible radiator
Fuel system - is walboro 255lph enough? Lines needed?

Let me know if I'm missing anything, likely am.

If i can find one I'd like to go for an ls3 or preferably ls7, most likely used.. i do have a friend that could help me rebuild it before installing if needed, curious what a shops labor would be for an install on average though?

 

O man, there are tons of Swap Threads on the Forum.

But yes you have most of it.