Hi,
I have a stock 1989 and I am thinking about puting aluminum heads hooker headers new cam (not picked out yet,sugestions?) 21/2 exhaust with flow masters, a cold air intake and throtttle spacer and maybe alittle more.

My question is I would like to aim for about the 400hp mark but was wondering at what point should I worry about breaking things like my rearend.

Thank you
ZiG's

 

There were stock C4's with more than 400hp, so I'd imagine you'll be alright. Do you have an auto or ZF6?

 

i think the rods r rated at 500!

 

if u pop the clutch too hard i would imagine the trans would go,if u have slicks and u dead hook, i would imagine the shafts would go,if u hit a wall with all that power, i would imagine, well u catch my drift be carefull!

 

ZF6

 

Do you have an A4 or a 6-speed tranny?

 

6-speed trany

 

Hi and welcome.
Your engine already has aluminum heads. They are usually referred to around here as the "D113's" from their GM casting number.

You can massage them and get slightly bigger valves for improved performance.
Of course you can do something like AFR heads or brodix or other brands too.

Cam. Do you have emissions testing you have to worry about?

With the 6 speed car, the weakest links will be the outer spindles/hubs of the rear wheels.

 

Hi,
No there isn't really emissions to worry about out here. As for the heads would it be a waist of money to buy just some eddle brock performers then? if so what else could I do for a good hp boost?
Thanks
ZiG's

 

You have aluminum heads already.Any Y/Y header will give you more than a 4 into 1.219 Lingenfelter cam.If you can delete the cats go 3" with Borlas at the end and an X pipe as close to the collectors as you can.Don't waste money on these stupid intakes.Leave it as it is and just cut the filter box intake as large as you can. What's a throttle spacer??? I have a fully worked 383 Lingenfelter and I'm pushing around 435 so 400 is out of the question with a few bolt ons.As for breaking rear ends you have the dana 36 most probably and if you drop the clutch and get a real good hook up right now you could well break something.

 

With a ZF, theres really nothing to worry about with around 400hp. It should be fine, but the clutch will wear out eventually.

Bear in mind that HP doesnt break things, torque does.

However the mods you have in mind are not sufficient to get there, the TB stuff is useless, and the cold air setups arent going to give what the manuf. states. A cam by itself will not get you there, you need heads and a new intake system to easily get 400. Read my website.

 

No, 6 speed cars come with Dana 44's.

I had a superramed 355, stock heads, mild cam, made 475 TQ at the FW (I forget the HP number), so his request of 400 is not too far out of the question. I would say definitely do not forget the intake.

 

89 ZF6 have Dana 44s. Did you want 400rwhp or 400chp. A 400hp LS2 makes around 340 at the rear. The 383 L98 I saw dyno with a mostly stock top end made 360rwhp.

 

To give you an idea of just how much it takes to get to 400 HP at the crank, i'll tell ya what i've got. I have an '85 and i've put Edelbrock aluminum heads with the biggest valves they come with (2.02, 1.6) and this bumped my compression up to 9.6. I've got Lingenfelter long tube headers with straight pipes back to SS Magnaflow mufflers (2.5" exhaust). I eliminated all the emissions crap as well.

Now with all that and doing the labor myself, it cost me about $2300. All this put me at about possibly 300 HP at the crank. To go to 400 your gonna need to bore and/or stroke that bad boy.

 

Sorry, missed the bit about the 6 speed I assumed it was auto.From what I read here 'tho you can do far more damage with a manual.My concern was about the shafts and u-joints. As for Vaders concern about torque according to todays posts on the subject it doesn't exist,it's all about gee gee's. Yep,I was watching as well.There do seem to be some wild claims about engine outputs with very mild modifications 'tho.Maybe all the experts have it wrong.According to Ecklers for around $1500 you can bolt on 225 HP without even opening the thing up.I should have gone that route and saved myself $$$$$$.I'm so stupid.

 

NOS

 

I have almost 700hp and it barely gets the job done, so I just add a little nos 300 shot I am their.14k later.To make HP in a vett you need lots of $$$$$$$$.I should have gone to mid america,According to them I could have made up to 250 hp with all their claims .
100 shot of nos and 700 $$ you can make some power.
Save your money enjoy your car and buy a 2008 with 500 hp and you will be happier

 

To get back on topic from the OP's question which is "how much could a C4 handle".

I have a modified 94 6-Speed LT1. Major mods include 383, 10.4:1 comp, AFR 190cc LT1 heads, crane HR 232/240 .575/.598, EM headers, 2.5" RT cats, 30lb/hr injectors, tunercat (self tune with wideband), Mcleod Twin Disk, 4.10 Viper Gears.

I'm estimating around 460 FHP based on G-tech pro readings and 1/4 mile passes.

Best pass with drag radials is 11.93 @ 117 MPH 1.739 60' in Texas on a hot and humid day.

In my experience with a 6spd C4, I would say the SPIDER gears are your weakest link (with aftermarket clutch). I've managed to destroy two sets of spiders so far with Drag Radials and mild launches. The shifts seem to be what is claiming my spider gears.

During the last repair I had the rearend shop setup my spiders as tight as possible. They didn't use the conical spacer that places preload on the rearend (which introduced slack and allowed the spiders to ride on the outer edge of the teeth thus breaking under shock). Instead they used flat spacers which do not flex (keeping the spiders togther utilizing all of their surface). The byproduct of this setup is that the rearend acts as an open diff. when no power is applied. As soon as power is applied the rearend locks together as usual. So far with this setup I haven't broken anything else. *fingers crossed*

How much can it handle? As much as the spider gears can take. More for an automatic, less for a stick car. Good luck.

 

 

Ok, I'm guessing that's aimed at me.
I found the old thread, but the pics are gone. I'll re-take a pic of the sheets later.
The crank HP was 373 @ 4500 RPM
crank TQ was 473 @ 4000 RPM

http://forums.corvetteforum.com/showthread.php?t=371285

I also re-read the OP's first post. I assumed he was going to re-work the short-block, but I was wrong. Still, high 300's is within reach.