I have been debating for the past few months what to do about an engine.. LS1 = way to much work and money.. LT-1 = maybe a little more money than I wanted to spend and still too much work, wiring, chip tune.. all that.. so now im down to a L98, cheap enough but from what I have read I dont think it will be the right choice since it cant breath up top.. the engine i want would have vortec heads and a pretty large cam so that too would require lots of chip work as well as a votec tpi manifold.. and even then the tpi wouldnt breath good.. so now we are down to the basic carb conversion.. cheap, effective, and all the power you wanna make, in whatever range you wanna make it in.. heres the combo I have planned, maybe you guys can give me some tips, ideas, let me know any bad ideas I have.. The main goal for this engine would be to beat a stock LS1 camaro.. oh the car the engine is going in is a T-5 3:42 posi .. ok 670 holley street avenger, vortec intake (edelbrock?).. stock vortec heads, ( the best casting number would help alot if you know it ).. roller block 2 bolt main 1 piece rms, LT4 hot cam or possibly even the cc306.. havent decided if I need to go that radical or not to get the effect I want. one thing I have no idea on is what pistons to use.. without knowing the vortec combustion chamber size I dont know where my compression will be.. thinking just a set of hyper flat tops.. pistons is one thing I will need help on deciding.. rods will be reconditioned GM units as well as the crank.. so basically a stock bottom end with better pistons, vortec heads, and depends on the cam I go with will depend on what valve springs I need.. I think I have covered it all.. any cam or piston suggestions?? and if you give cam info let me know what springs you would suggest.. Thanks alot guys

 

oh totally forgot something very important.. i will be hooking up a 100 or 125 hp shot of nitrous to this engine but ONLY to be use if needed.. i rarely run at that track, its mainly me and my buddies picking on the local cars.. so if im loosing by a nose or whatever I might spray to get the edge.. but it will have the nitrous non the less.. hell its nice to purge anyway..

 

If you search on "vortec", I'm sure you'll find the casting #'s. I don't recall off the top of my head.

Vortecs have 64cc heads (the 350 versions, anyway).

If you're going to spray, better go with cast or forged pistons. Forged is, of course, safer.

Why a Street Avenger? Why a vacuum secondary? With manual tranny, and most performance applications, mechanical secondaries are much better.

 

I was just under the impression that the street avenger was the "easiest" carb to own.. Since I am going from EFI to a carb I just didnt want to deal with the problems I hear so much about.. I know there will still be adjusting to do no matter what but I just wanted the carb with the best "manners".. If the street avenger is a bad idea just let me know, there are 100's of choices so that can be changed easy.. anyone else have any ideas?? i think since I will only spray once in a blue moon I will go with cast, unless of course I can get forged for close to the same price..

 

The step from SA to double pumper isn't that big. If you can tune the primaries of the SA (which it will need), you can tune the secondaries of a DP.

Right now, the cost difference of $240 for a set of forged and $75 for a set of cast may seem huge. It won't seem so much when you're taking it apart after a cast piston fails under spray.

 

yeah i am going to go ahead and have it assembled with forged pistons.. better safe than sorry.. i just thought since i was using a fairly small shot that cast might hold up ok.. the one question still remains, you think this motor will have what it takes to get me into LS1 territory?? its pretty mild other than a cam.. just stock vortec heads, stock bottom end with forged pistons, and of course as stated above its going to be a carb setup with a T-5 and 3:42 gears.. I think as for the cam since I have tried before to get recommendations on this site with not much luck I will just call and see what they tell me...

 

Peak power close to LS1? Probably. Area-under-the-curve power close to LS1? Probably not. Keep up with an LS1 car? Certainly not after the T5 grenades.

Unless you are comfortable sorting through cam catalogs to pick one for your application, you're best off getting a recommendation from the cam manufacturers themselves.

 

thanks for you posts on this.. I figured that the peak hp would be close, but I didnt know if that was going to be enough or not.. so basically on a dyno it will read what LS1's do but on the track/street it wont be able to run one? what about on the spray? surely that will get me by them.. oh and dont worry, I already know the T-5 wont last long.. a T-56 is being put into the budget, which is also a reason I cant go too wild on the engine

 

They dyno should give torque @ RPM from ~3000 RPMs up (where they start depends upon the dyno - some lower RPMs, some higher). Since HP is calculated (torque times RPMs divided by 5252), you will get that from the torque valuse. Plotting torque and HP vs. RPMs will give you the dyno "curve". What I was saying was the peak value your engine will produce may be close to a stock LS1, but are RPMs below where the peak comes, the LS1 will likely be higher. Thus, the "area under the curve" for the LS1 will be more. Spray may help improve the low part of the curve. But, that's cheating, anyway.