porformance mods for 3.1 need opions

[rx191]

i have a 91 3.1 out of a camaro and i'm going to put it in a lotus 7 replica, i'm looking for a 180-200 hp. the motor will be matted to a manual trans any sufjustions on witch to use would be help full to. the car will have custom side pipes on it and i was wthinking of running a large cam a carb maybe do some head porting and larger vales or maybe runa set of gen 2-3 heads i neeed anyone opiion. thanks

[sharkey]

180hp isnt much of a problem if you want to run gen 3 heads, however you will need to run fuel injection to use them. you would need to fab up a custom crank trigger for the dis ignition, being a distributor wont clear the upper intake with gen 3 heads. the other option would be a 3.4l f-body block as it has a crank position sensor setup on it. or being this is a full custom install and mounts need to be built anyways, you could just use a complete 3400.

if you wanna stay carbed and keep it all simple, stick with cast heads. get some forged pistons (gonna have to be custom, non avalible for the 3.1l ironhead) with higher compression, a nice lumpy cam like a crane 272, port the heads, SI stainless valves, port the heads and intake. i think guys have the best luck with the offenhauser intake and holley 390cfm carb.

[SappySE107]

If you go with SI valves, make sure you rework the backside cause they hurt flow in stock form. Iron heads are your only real option for a carb, and im going to have to recommend going fuel injection. There is software to do your own tuning if you go with a 91 or so computer out any FWD 3.1 car and wiring. Gen 3 would be your best bet and honestly, I would just start with a complete gen 3 motor as they aren't that expensive.

I guess the best place to start would be your budget cause there are so many ways to get 180-200 hp that id be listing stuff all night. Im a little too busy to be doing that:P

[rx191]

i'm a fuel injection guy also but i think a carb really would be simpler in this case, plus i really don't want to get anther engine this has been sitting around for a about 3 years and it's time i did something with it. the car will only weigh like 1200 pounds complete so even with a stock engine it will fly i just want as much power as i can get with the least amount of money same 400 in the engine, i figure i should be able to do get stainless valves, a good intake carb, rockers, and a cam the ehad porting i can do myself as the machine work.

[Doubt_Incarnate]

your buget will definatly be a limiting factor. i have a gen 2 sitting in my garage im tryin to decid eif i want to go hybrid with it. but as it sits, i got like $2000 just sitting there.

thats a set of +1mm pistons, the required boreing to get them in there. a crane h260-2 cam, crane gold rockers, heads checked for cracks, resurfaced, new valves, valve guides, valve stem seals, new springs, new locks, new timing set, new gasgets, gapless rings, new head bolts. i'm sure i missed a few things, but it can quickly add up. and i dont have headers either.

[rx191]

i bet a good chunk of money was spent on machine work hu?
i get all my parts at cost and all of my machine work is free ( ido it myself) why are you running gapless rings without a high compression ratio or a turbo they are useless, low tension rings would have been a much better investment. i don't plan on changing th pistons at first i'm just going to ring and bearing the motor and put new oil pump in it. the cost on everyhting is about $120 and i'm not including that in my budget the stock bottom end of these engines are morethan good to over 250 in stock trim and with very little work good to way over 500. i will problewy use arp rod bolts for good mesuare and then spotpee and polish them too. getting 200 hp from a 3.1 iron head shouldn't be hard at all, thats only 60 hp over stock and with the right parts it is very doable.

[Doubt_Incarnate]

I too have a 200hp goal. i'm using 3.1 iron head pistons with the aluminum heads. 11:1CR or so. and the heads were like $400 in shop work and parts. if i knew what i know i now i'd probly made better choices in selecting my parts. i think i may be able to use 3400 head gaskets to bring it down to a more friendly 10.7-10.8:1. with the car youre building headers shouldnt be a squeeze so you shouldnt have problems making 200. for what DD2K is worth... its guessing my motor is at 191hp.

if you can machine things, maybe you can make a peice to fit under the valve cover on a 3x00 head and be able to make a custom intake and run a carb with those heads, they out flow the iron heads and maybe you'd be on your way to 300hp.