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okay ladies and gents of thirdgen.org, i am wanting to make at least 550 hp out of a 89 4 bolt main 383 in my 1988 firebird currently equipped with:
callies dragon slayer 3.75 crank
l2304 .30 pistons
luanti street race rods press fit
crane gold race roller rocker arms
crane hardened push rods
crane roller lifers
crane double roller timing chain
sr torquer heads w/76cc combustion chamber 2.02/1.60
stainless valves
i have a crane compucam but im not sure if thats the best option. i am going to be using a TPIS mini ram and want to keep it emissions legal. i also am going to swap to some 64cc chamber heads but not sure what kind too use. I know i want aluminum heads and i have heard great things about AFR but what do i know? i do not want any kind of boost and it will run on pump gas (with an octane booster cause i figure at least an 11.1 compression ratio) I do not want a drag car, i am building a sports car so i want it to make plenty of top end power. any advice would be much appreciated
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well i want to make the power all on motor because of the durability issues that adding boost can cause. and while it will be a weekend street car for the most part i do plan on taking it to a few road courses here and there.
You're asking a lot if you want it emissions legal. Yes the AFR heads are good, probably the best 23* heads for the money. I wouldn't waste money on octane booster for 11:1 compression, with good aluminum heads, you should be ok with 91 or whatever AZ's highest is. Call up and talk to a tech about a camshaft choice, call several companies and see what they say. Tell them your combo and what you're goal is and they should be able to get you in the ballpark.
__________________ Best times to date, motor pass: 11.81 @ 114.55 1.63 60' 10/18/08
nitrous pass: 10.49 @ 126 mph 1.42 60' 10/18/08
350, AFR 195 heads, Eagle H-beam 6" rods, Victor Jr,
750 Race Demon, ProMagnum RR's, Hooker LT, TH400, Spohn T/A and C/M
Bump for someone doing practically the same build.
Looking for 550-575 out of a 383 W/MR all motor. In particular I want mid 10s (thats where the hp ## came from). My reasons for not wanting boost is that I dont want to over-complicate the engine. I just want a mean 383. My reasons for not wanting N20...im a Marine. Rolling past the gate with a nitrous bottle would be alot of fun. Even if its possible I take pride in my clean record as a Marine (knock on wood) and I just dont do things to mess with that.
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2nd Marine Air Wing 3rd Gener, Cherry Point NC. Semper FI
my confusion comes from intake runner volume in the head? 195cc? 235cc? and what intake/exhaust volume? and valves? thats also good to know i can use regular 91 gas for 11.0:1
btw f-body demon thank you for what you do for us and the country.
As you are surmising forget 550hp with those heads. The AFR's will go a long way towards your goal but you will need all the supporting mods. Those will include a first class intake and exhaust system along with a fat wallet. I would talk to a cam grinder about a custom cam.
While I have the engine out im going to do some serious chassis overhauling as well. As for exhaust im going to use hooker headers/Y pipe, magnaflow hi-flow cat and, a magnaflow cat back. The intake will be a TPIS mini ram using a twin 58mm throttle body. Im fairly confident in that as a supporting cast for what im am trying to achieve. the only thing missing is a fat wallet... Thak you for the cam advice ill ask you guys because i lack any experience with custom cams who whould you guys contact? Crane? Comp? Lunati?
Dyno simulations show the AFR 195's will support in excess of 550 hp with the right cam and compression ratio.
I've used a carbed application on a Victor Jr. intake for this example.
Comp XR288HR cam. 288/294. .555/.575 w/ 1.6 rockers. Installed straight up.
1 7/8 LT headers with optimized collector length.
11.1:1 SCR.
8.5:1 DCR.
549 hp at 6500 rpm.
I understand you're going the EFI route however comparable results should be obtainable with off the shelf parts.
As for emissions legal...you would have to talk to our California brothers about that one. That may be where the custom grind comes into play.
Alright thats sounds good for heads. i like that the 195cc AFR's come in center bolt designs... 1.6:1 rockers appropriate? should i go 1.7:1? a combo 1.6:1 intake 1.7:1 exhaust? just probing the minds that know more then me
I would consult with whoever designed your camshaft as to what rocker ratio to use. Normally I would not go over a 1.6:1 ratio. I will be using a rev-kit and using a 1.65:1 ratio with my new build.
What kind of benifit would he see if he went up to the 215 AFRs? I mean if he is going to be spinning a 383 to 6500, a 215 should be within the useable limits correct? I know that the 195s are gems but if he picked up the additional 15cfm given up by the bigger ports wouldnt he see a worth while gain? Is there any way to make the last 25 hp in the top of the engine? Shy a power adder?
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2nd Marine Air Wing 3rd Gener, Cherry Point NC. Semper FI
I'm gonna say forget emissions legal and 550 n/a hp out of a 383. Dont think its gonna be doable. Miniram doesnt have egr anyway so its not technically emissions legal, unless you buy their egr kit.
Still dont think you'll beable to tame the 550hp 383 enough to pass emissions. Idle will be lopey.
My motor was 11 to 1 383 with Stealth ram, AFR 195s and a big 230/245 cam on a 109 lsa. just over .600 lift. Revved to 6250 at peak hp, flatlined it to 6500 and started dropping off after 6600 where i shifted most of the time. Wouldnt have a shot at passing emissions. I dont think I was near 550hp, probly just 480-500 based on 400whp dyno and 20% loss thru auto.
550 hp 383 is doable with a mild solid roller and AFR 210's. Keep it 11 to 1, solid roller in the 240's range at .050, high 500's lift, closer to .600 or so the better with 210's. 1206 miniram will be necessary for the 210s. Look to make peak at around 6500 rpm shift by 6800.
Hydraulic roller could be possible too. I was gonna do a single plane EFI conversion and a big 240/243 on a 108 cam with .57x" lift. Would peak at 6500 or so and carry to 7000rpm. Should have made well into the 500 hp range, i'd say and hope around 525-540hp, or 430whp. Something along those lines will work, a cam in the 240's duration that will peak at 6500+ rpm. valve train has to be VERY strong/stiff and light to handle those rpms with hydraulic roller.
Of course there was a corvette guy that had a 370 motor i believe with AFR 210's and a somewhat mild 230/236 cam with .6xx" lift hydraulic roller and made mid 450whp range or something ridiculous like that. Thats well over 525+ hp on motor I'd say
Solid roller is your best bet but either way go AFR 210's or comparable...which there really isnt anything that is too comparable at this time.
thank you Orr89RocZ for your input. that is all really usefull info man. the emissions here in AZ are pretty relaxed. I had already planed on getting the egr kit for the mini ram but i just need to be bellow 2.20 c02 loaded and 1.60 at idle and 220/160 ppm hydrocarbons loaded and idle respectivly. and i need a smog pump and cat and thats it btw do those 210cc heads come in a center bolt valve cover design?
The 210's I am not sure, but the 195's definately come with both bolt patterns. 210's i think have egr crossover passage in the head like the L98 heads but again, have to double check that.
A cam in your setup will have to have good duration but keep it wide on the lsa to get it to pass emissions. I'd seriously look into a custom grind.
There are some TPI guys here doing mid high 300's whp on 350 motors which is like mid higher 400's crank hp and doing it smog legal. So you could make even more power with a 383 and somewhat more relaxed emissions.
THE TUNE IS GONNA MAKE OR BREAK IT THO. That is where your gonna have to really take time to get it to pass.
ok dumb question, my current block came out of a 1989 pickup. it isnt an LT engine, my car originally had a tbi 305. ive already got all the things i need to convert to tpi for the mini ram, but would the 210 lt heads fit on that block?
ok dumb question, my current block came out of a 1989 pickup. it isnt an LT engine, my car originally had a tbi 305. ive already got all the things i need to convert to tpi for the mini ram, but would the 210 lt heads fit on that block?
Yes, the heads will bolt right on. However, I'd prefer you get the Competition Ported 195 Eliminators. The stock 195 Eliminators have already made 516 HP with a 230/236 XFI cam and the ported 195s should put you close to your goal with a SR cam of around 242/248 @.050. Remember, when moving from a HR to a SR, the .050 duration needs to be increased by about 10 degrees.
Porting the Mini-Ram may be needed though, since your goal is so high.
Comp 195's are good heads if you want to spend more money on them. 210's have same flow if not slightly more , cheaper than the comp 195's and already setup with solid roller springs. 210's will out power the 195's at over 6000 rpm where you'll need to be
They do flow abit more but I really havent heard much on the comp 210's. You hear alot of talk on the comp 195's but nothing much on the 210s. For a 383, i dont think you'll need comp 210's
With your goal of 550 horsepower you are going to need all the help you can get. The Competition ported will get you closer to that goal. If I was you I would call Tony Mamo at AFR and get his opinion. He deals with these issues on a daily basis and tell you exactly what you need. That is a pretty high goal you are trying to achieve. No matter the intake manifold it will need some serious work to do what you are trying to accomplish.
14psi, street tune 
