engine help

[Blackbetty]

i have 85 corvette would like to build my motor from 230 hp to somewhere in the range of 300+ hp still want daily driver but with a lost more snap any sugestions on piston size heads ect would love to hear your response.the more the better

 

[afree]

Check out www.tpis.com, they are just one of several companies that offer excelllent after market parts for the L98 engine. To get up to around 300 + HP is not very difficult. Start with a good free flowing exhaust system, change out the chip and swap over to a K&N air filter with an open lid and your practically there. The sky is the limit when it comes to adding power it really depends on your budget and how much power you really want.

 

[Hrtbeat1]

300 awww come on ... that should be pretty easy. I agree headers and exhaust will get you most of the way there if not all the way. I guesstimate around 40 HP others say around 70 HP. To start off try some of the little free mods, ie TB bypass, cut air filter lid, descreen the MAF, removing the frisbee (not sure if the '85 has one.) Those should be good for 5 to 10 HP, but be forewarned its addicting, once you get to 300 you will be wanting 400, ect, ect .

I guess the real hinderance you have is the iron heads. I say hinderance due to the weight but some people have gotten good results out of them, not sure how much work had to be done. A good set of AFR 190 aluminum heads with 2.02/1.60 valves ready to go would most likely get you well over the 300 mark and cost around $1500 to $1800. Check out Sallee Chevrolet in Oregon they are really good to deal with and know their stuff about making HP.

Enjoy and Save the Wave

 

[max]

Maybe I can use your topic BlackBetty , to chime in an ask some questions , don't get angry , I'll put a beer to ya .
Thing is , here inna place I live not much to choose for considerable money ..
So if the opportunity arises , usually I start thinking .
There is possibility to get LT1 heads , intake manifold , and cam
I have L98 91 , 245 hp , I want to have 400 hp .
So , what's the way ?
And what do I get with the cam at least ?
What's strange my exhaust is kinda not good , you know it has only big cat in which the air tube is going , and then it just goes out of ends , no silensers
I know That you can lose on bottom toque with no resonators on , so if i eliminate cat should I put some resos in ?
I have K&N already , no open lid , will do bypass ..
Just basically wanted to know your opinion , guys on LT1 thingies ..
max

 

[Hrtbeat1]

Max

The Generation 2 Chevy motors (LT-1/LT-4) are not compatible with the first generation motors (all prior motors). Gen 2 motors are reverse cooled, which means the coolant goes the other way (from the head to the block then to the radiator) plus the Gen 2 motors don't have a traditional distributor, they use the optispark which is driven by a pin on the camshaft. Yes the intake can be modified to work with Gen 1 motors, but it is not as easy as just bolting it all up.

To get the 400 HP you are wanting you would need to get a really good set of heads, Headers with a free flowing exhaust, a good camshaft, a custom chip for your computer, and have some work done on the intake manifold to improve air flow (porting.) You could go with a Bigmouth intake and large tube runners and just port the plenum some (probabally easier than doing all the work on the stock unit) or go with something like the MiniRam intake (which is basically the same as the LT1/LT4 intake.) I'm not saying this combination will get you to 400 HP but it should be at leasst somewhere near that.

 

[max]

Thanks Gerald . Your reply is what I was waiting for
Well , as I get it , I do not need LT1 cam for L98 , nor heads nor intake ..
But you know , I've been observing here heads porting and polishing so to say onna knees . And next question is : is something possible to do with them heads I already have , port them myself . Or is it pointless ? Is there any improvement possibility ?
Basically I could do headers myself , they wouldn't be as exactly produced as some aftermarket headers ofcourse but would be close , I have a friend who could make a calculations and then it would be just grinder and welder and grinder again . There is also ceramic coating afterwards ...
Duplicating exhaust system is too not some space technology
But I just wnted to know what to do with what I have ...
Ofcourse cam is something else , that I'll have to buy
Chip ? I also observe here 2 friend vehicles with AEM and some russian unit which is not so expencive as AEM but pretty good , so one could map it all as one wishes ...
Whadda ya think ?
PS sorry , if what I wrote her seems kinda bit erratic , I just partied hard here , no worries , she is ińna garage

 

[max]

Oh , another thing . Friend offered me to raise the compression ratio by polishing block a bit , or heads ... You know , to make the chamber less in volume ?

 

[Edmond]

Ever consider a crate engine?

 

[Hrtbeat1]

Oh , another thing . Friend offered me to raise the compression ratio by polishing block a bit , or heads ... You know , to make the chamber less in volume ?

The heads on your '91 are not bad ... they could use some cleaning up I'm sure. They are kinda limited with the valves they have 1.94 intake and 1.5 ehaust. They can be opened up a bit but you can only get about a 2 inch intake and about 1.55 exhaust due to clearance in the 58 cc chamber. Porting is as much a science as an art. Without the use of a flow bench you are at best guessing. I've seen guys do their own porting only to have the car run worse (the air flow was not even for each cylinder.) One thing that helps is going with 1.6 ratio roller rockers.

Cam ... yes you can use the LT1 cam. The GM "Hotcam" was made for the LT4. You just have to drive the pin for the optispark in for clearance. It is a popular cam to use partly because there is a kit with the cam, 1.6 rockers, springs,and retainers. A better cam is the TPIS ZZ-9 or ZZ-409.

Not sure about the AEM or the russian unit, but its not really rocket science. If others are using it I guess it works. Maybe you could get some info from them.

I don't know that I would mill the block or the heads. You can gain almost 1/2 point of compression by using a thinner head gasket. The stock gasket is .049 inches thick, I've seen head gaskets .031 and even .020. You have to check valve to piston clearance ... contact = bent valves or broken pistons (NOT GOOD)

 

[max]

To Edmond: crate engine is , like I get it a ready tuned up engine in a box with a pink ribbon , they leave at your door That means $$$ and for me that means $$$ x 2 , as I am not the states' resident
And I just would like to get something from what I already have .
To Hrtbeat1 : well , in that you are right , we also have some kind of flow bench here , so I think I would do heads with that , not myself .
So , the LT1 cam , that I am offered here , is one fifth the price TPIS wants for ZZ cams . I had no time yet to compare , but I suspect that all parameters are better than L98 cam : duration , lift , overlap etc
So , I guess I shoud buy it ..?
Rockers , well Yeah , I guess I'll have to go with 1.6 .
Well thanks , some picture I got with your help .
Only one thing , will L98 comp handle well if for now I go with LT1 and 1,6 rockers ?
thanks man ,
max