231v 6
- Thread starter Jwh
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I hear ya. Ive got the intake and 4bbl. Was wondering if headers would be fit without mods. And maybe 373 gears. ( plus cam and lifter set.)
Let's step back for a second.
Tell me, you said engine is fresh, any specs on the rebuild? What heads are you running? Bored over? What pistons?
On a 231, adding a 4bbl really doesn't give much hp on its own. Neither does exhaust. Do all that and... maybe 20? 25 more? If tuned right.
Your friends are if compression is bumped up, and what block/crank/rods/heads you got. A decent number of the 86-87 109 block castings came factory with the same rolled fillets both crank/rods like the turbo cars... normal n/a cranks earlier years only have one. 109 is a superior casting with more strength in lifter valley as well.
Desirability is basically 86-7/85/anything older (excluding the 4.1s of course). Late motors also got the better 8445 heads as well, even n/a.
Best cheap mod if your bottom end had the better stuff and you're built for it is running a bit of nos - the added 4bbl gives you the fuel enrichment ability, if tuned for it, to pull it off.
The other part is pick a rear gear that matches your trans and tire diameters to get most of your driving in the rpm sweetspot where you do make what power you will.
And before hotrodding/beating on it, decide on a new trans - that 200c ain't gonna do anything for you very long
Tell me, you said engine is fresh, any specs on the rebuild? What heads are you running? Bored over? What pistons?
On a 231, adding a 4bbl really doesn't give much hp on its own. Neither does exhaust. Do all that and... maybe 20? 25 more? If tuned right.
Your friends are if compression is bumped up, and what block/crank/rods/heads you got. A decent number of the 86-87 109 block castings came factory with the same rolled fillets both crank/rods like the turbo cars... normal n/a cranks earlier years only have one. 109 is a superior casting with more strength in lifter valley as well.
Desirability is basically 86-7/85/anything older (excluding the 4.1s of course). Late motors also got the better 8445 heads as well, even n/a.
Best cheap mod if your bottom end had the better stuff and you're built for it is running a bit of nos - the added 4bbl gives you the fuel enrichment ability, if tuned for it, to pull it off.
The other part is pick a rear gear that matches your trans and tire diameters to get most of your driving in the rpm sweetspot where you do make what power you will.
And before hotrodding/beating on it, decide on a new trans - that 200c ain't gonna do anything for you very long
Don't mean to be negative - just truthful. Option 2 sell the 231 and bolt in a 350. Seriously I've been in your shoes. My Regal started out as a V-6 and your really not going to get any bang for the buck you spend. A gear will make it feel better. Check out a previous post - 3.8 v6 231 engine mod
The best heads are the FWD 3.0L head castings used on the '89 turbo trans am, but there aren't any RWD non turbo exhaust manifolds for these heads, so unless you can weld your own.... These heads can probably make 15-20% more HP than the RWD heads, but nobody will ever know it. I've ported a bunch of the 8445 and earlier heads and the FWD 3.0L heads have much better port shape and larger short side radii... and a smaller combustion chamber for a higher compression ratio.
The 3.8L doesn't like to rev over 4700 RPM. Even the turbo cars with fresh valve springs hit a wall above 5200 RPM with stock heads/cam cramming 23 psi of boost into the motor.
Ported/milled 3.0L heads, custom headers, a larger cam, 4bbl (or a TR FI set up with a megasquirt) and I can see 180-200 NA HP as possible, but you can build a 350 or swap in a junkyard series II for less.
The 3.8L doesn't like to rev over 4700 RPM. Even the turbo cars with fresh valve springs hit a wall above 5200 RPM with stock heads/cam cramming 23 psi of boost into the motor.
Ported/milled 3.0L heads, custom headers, a larger cam, 4bbl (or a TR FI set up with a megasquirt) and I can see 180-200 NA HP as possible, but you can build a 350 or swap in a junkyard series II for less.
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