david_351

Hey guys, while Om currently collecting and fabricating parts, and trying to overcome problems with my twin turbo 305 crossfire 83 Z28 project, I have two other projects on the go, one is an 84 Crossfire Vette, which will be a 383. That's a long term project. The last project, is one I'd like to finish by august or September, is an SBC Fiero transplant.

Now over on the Fiero forums, a lot of guys diss the SBC and LS1/LT1 as not being as fast as the supercharged 3800 V6. Which, in the case of the Fiero, is true often. A 275-300 horsepower 3800SC will often out run a 450hp 383 simple because the V8 has too much down low torque to be able to keep the narrow wheel width, light weight Fiero wheels from just spinning.

So my plan, to redeem the SBC in the Fiero world is to build a super high winding 283. I have access to 3 or 4 free 283 short blocks. I'm thinking with a quick rebuild, new pistons, gaskets, arp bolts etc, and a set of Trick Flow 175 heads with 1.94, 1.5 valves, and milled to produce approx 10.5:1 compression, topped with either a Victor JR Intake and Holley 750, or a dual carb tunnel ram with dual 450cfm carbs. I will use a custom solid roller cam.

Do you think 350hp is possible at a high rpm 7000+rpm?

I think this engine would be perfect in the Fiero, the car is an 84 4 speed manual with 4:10 final ratio. This engine won't have too much torque low end that wheel spin shouldn't be a huge issue, and I think this engine would show the 3800SC guys that SBCs are still king.

What do you guys think? Anyone gotten 350(flywheel) hp out of a 283 or think it's possible given the high winding nature of the engine?

AlkyIROC

Why? If your goal is 350 HP, it's easier and cheaper to build a 350, 383 or 400(406).

The 283 is an archaic engine. Blocks are free because there's zero demand for them. Even a 305 is a better choice.

There's a local around here with a SBC in a Fiero. Also has a 6-71 blower on top of it. He went through a lot of transaxles trying to get power to the ground. Toronados didn't work, Caddys were strong but not strong enough. He eventually built his own for around $10,000. The car is capable of 9 second passes and is street legal. It's cool seeing the blower scoop above the roof and the wheelie bars sticking out the back.

Your post however has very little to do with third gens so don't expect much response and it will probably get closed soon.

david_351

I'm aware it's easy to build a 350 and bigger to such power levels, with ease, and have built many, however, as I described, in the Fiero, the chassis doesn't support wide wheels like a Corvette or Camaro can handle, and the curb weight is 2500is lbs, so a 350 with 350 horse is going to make power at a much lower power rpm level, and more importantly, the 350 or 383 etc would make way to much torque, causing the massive traction issues. Power is only good if you can get it to the ground. For example, I know of one guy with a 425 horse 383 in a Fiero and one guy with a 280-300ish 3800SC, and the 3800 V6 car goes almost a second faster down the 1/4.

Hence the 283, it's down low torque will be lower, allowing for less wheel spin and more traction, and it's short 3" stroke and extremely durable crank make revving past 7000 even to 8000 quick and easy. So producing the same power, but in the upper 6000/lower 7000 range would be a benefit in the lighter car.

Believe me, in my Camaro their will be a 350, the Vette is getting a 383. Here I'm just wondering, for those with experience with the short stroke small blocks, do you think the above combo would net 350hp somewhere high in the rpm range.

RedRokkit

The great 3800sc vs V8 war.....In a Fiero it is ALL about getting the power thru the drivetrain and to the ground without breaking things, or spinning to a lesser extent. the trans is usually the weak link in the SBC swaps as all options have their compromises, being strength, less than ideal gearing, or insane fab and cost.....Its easy to get into C5 territory when building a V8 Fiero. And wide wheels aint a problem on the Fiero either its just expensive, even more so if you do it the correct way...see attatchment...... then after you got your nice wide tires on it start saving for a wide body to cover them.... ok done yet? no ok.... now that you have traction, stuff WILL start breaking. you could completely blow the budget like the orange transverse BBC swapped Fiero mentioned above, and stuff will still break...maybe if you stuff a Porche or Ferrari trans in it
but seriously Id go with the FWD Ls4 trans or a built 4t65hd niether are bolt up affairs ....
the motor will be the easy part imo......cam selection will be key to spinnin it high and keep making power, id definitely go with a 4" bore....not a 305 as someone mentioned but maybe a 302 or 327 for a bit more cid to help...and with a single plane intake, retard the cam, good springs.....

I hope you do it.... im on my third Fiero, an 86 2M6 M4 SE... and rite now im thinkin 4.9 with a fukton of N20....stuff will break, but the only custom part ill have is a flywheel...

Jim85IROC

iTrader: (2)

I wouldn't build a 283 just because you want high rpm power. A 350, 383, or any LS can still make a better platform for high rpm use than a 283. There's no shortage of guys with huge-cammed LSx motors that are lazy at low RPM and make ridiculous high rpm power. If you insist on a small cube motor, I'd consider de-stroking something with a larger bore (like GM did with the 302). For high rpm, you want good heads with a lot of airflow potential, which you're not going to get from a motor with a tiny bore that requires the reuse of garbage heads.

With an EFI LS, you also have the ability to tune in torque management at low rpm in order to overcome a lot of the traction issues. That would also seem to be a far better solution than intentionally building a boat anchor motor.

AlkyIROC

Also, high rpm depends on the quality of the internal components. I spin my BBC to 7400 rpm even though I could easily take it to 8000 safely. Displacement means nothing for engine rpm.

david_351

I'm well aware of high rpm large displacement motors, the big block Chevs are one of the best factory high RPM motors out their. It's the short stroke Im after. As you all know, short stroke engines tend to rev faster into the high RPM band, yes a 302 would be nice, but the only thing I could destroke(without spending mega money on machine work) would be a 327 due to the journal sizing. Now where I am located 327 short blocks go for more then 6.0 LQ4 truck motors. 327s cost approximately 4-5 times what a newer, better 350 costs around here. So yes, while I agree with you a 302 would be awesome, it's just not really feasible. I know your all chiming in about displacement, and I totally agree with you, for a Camaro or Corvette I would never go smaller then 350. But for a car with a curb weight 700lbs or more less then that, a smaller motor can make sense, if you can wrap your head around it.

Also, 283s featured some of the best, strongest cranks ever from the factory. So if you have four of them, the odds then one of the cranks is still in decent shape is pretty good. Saving money on an expensive aftermarket forged crank a 350 would no doubt need to safely spin 8000.

AlkyIROC

Sure, back in the late 1950's. Technology, castings and metallurgy have come a long way since then. Camel back heads were also the hottest thing on an engine at one time.

If you want to build a 283 then go ahead and build it. Nobody here is going to agree with you that it's the right thing to do when there are so many better options to pick from.

RedRokkit

I get it....Id use a 4" bore block so you can get some good heads on it, hard to get high rpm power without a good Head/cam setup...3.75 bore blocks suck at upper rpms unless heavily worked over, and its still a game of compromises....If I remember correctly 283 is like 3.8ish.....

the way I see it is that the cam dictates your rpm range, and you need the heads and intake to support it, and most good heads have big valves that can shroud in a bore less than 4"

Z28ricer

iTrader: (2)

Not true, you can use any newer gen 1 sbc 350 block with a 1 piece rms, you just need the crank out of an L99 (4.3L baby LT1).

Casey Butt

I say if that's what you want to do and are willing to spend the money then go for it. I see no reason that a small displacement engine like that with high flowing heads like the Trick Flows (at least for a 283) wouldn't rev like a demon and have no problem making 350 hp. Of course, no one's going to argue that a higher displacement engine wouldn't make more, but that's not really the point.

T/Aperformance

If I was going to do a build like this, I would take that 283 and bore it all the way out and install 4 inch sleeves. Have splayed 4 bolt mains installed, Now you can install the heads needed like the old camel hump heads, And get the same cam that came in the old 302, Basically building The old 302, High hp and low TQ #