Max Power for carb. 2.8L

[82FirenzaS]

Ok, I own a 1982 Olds Firenza S hatchback I am loking to replace the 1.8L I4 with a 2.8 V6, what is the max hp I can get with the carbed version with dual exhaust? Thank you for any help.

[Doubt_Incarnate]

it depends on the $ you have to put in it. you could do use a the original 1xxhp 2.8, adapt a holley 2bbl for a few more ponies. maybe try to get the rwd intake from edelbrok and the 4bbl top for it and use a 390 carb, you can get 200hp, if you have headrs. otherwise you can expect 140 or so id presume, add a cam and the H.O. pistons an you can get maybe 180, but the exhaust will be most benificial if you can do up some headers. the fireo has "high flow" manifolds. so maybe those would help, but you need to make your own y/downpipe.

[82FirenzaS]

200hp is my goal for now, I am going to have the stock heads ported and polished, and pretty wild cam, an edelbrock torkerII intake, a 390cfm carb, custom headers running through a dual 2.25" exhaust system with glasspack mufflers and dual "boom tube" tips. I have heard that running duals causes power loss. If so by how much? Thank you for any help.

[Doubt_Incarnate]

the duals effect lowend power. it should help top end power, but you lose lowend. somehow lowend seems to disapear if it doesnt have to work against anything. you should be faster with duals, but it wont feel so right off the line.

[82FirenzaS]

Ok, thats cool then. Now what to do with the 1.8? It only has 121,890km on it. I will probably wait till it dies before I swap it out. Thanks for your help.

[X11_STE]

Um, the 2.8's were torque motors all along so any low end performance loss would be pretty negligible. Besides, even if there was a noticible power loss, how hard would it be to adapt your driving skills to keep the rpm's above 1500? I honestly dont believe there would be any loss because I have an X-11 with this set-up and the former owner (who I believe to be very honest) told me he would put the car into 5th gear and STOP and set the rpms drop to 300 (yes 300rpms!) and take off.
BTW, good choice of motors.

[Doubt_Incarnate]

i thought the x-11's were all 4speeds. even in 86 the cavlier didnt get 5 speeds with the v6. not till 87.

it is a torquey motor, but it is also small, reletively. i used to let my car climb up hills at idle with the 2.8.

[82FirenzaS]

Yeah, I can keep my rpm's above 1500 except that my car is an auto. Oh well, thanks for the feedback.

[X11_STE]

Yes, the X-11's came STOCK with only 4 speeds, but then, this car aint exactly "stock". Cavalier, Fiero, Celebrity, 6000, and a host of other 5 speeds will fit into a X-11 body.
Your car is an auto? OK, so put the set up on it and DRIVE IT LIKE ITS A RENTAL!!!! Again, biggest issue I see is that the floats will be on the sides so when you take sharp corners, you BETTER have the RPM's WAY up or the motor WILL dog and bog.

[82FirenzaS]

I don not think I will "drive it like a rental" but I may put in a manual valvebody so I can manually up/down shift. I wasn't planning on a sidedraft carb setup I was planning on the conventional carb over manifold setup. Thanks for you help. Additional feedback is asways welcomed.

[Doubt_Incarnate]

when i first started my project i talked to a guy at jegs about the edelbrock manifold, he told me since the carb was a square bore pattern i could turn it to suit my need. i dunno if he was pulling my leg. glad i went with FI.

[X11_STE]

Well, perhaps there are 2 designs of holley 390's but I know from looking at mine, it cant be front to rear (otherwise I would!). The holley is a down draft, side bowl carb, not a side draft (there is a BIG difference!!). Why bother putting a manual valve body in? I mean if you wanna shift manually, slide the shifter into L1 and go from there, wont hurt the tranny unless you overrev. I am so glad my cars a stick, its much easier to control the RPM's.