I've been playing with desktop dyno 2000 cause I'm rebuilding a 305 for my firebird (dont start the 350 crap okay, I've got a 305 to work with and thats that.) So this is what I've come up with, just wandering what kind of reliabilty I could expect.

 

What do you mean reliability. You listed nothing at all that would even give us a clue. What parts are you using? Whos doing the work? How much are you spending? How high are you gonna spin it?

Good luck with that waste of money, i hope your happy spending more for less.

 

Forgive me for being new to thist stuff.

Holley Street Avenger 670CFM 4 barrel carb

Holley Street Dominator dual plane intake

Master rebuild kit from Performance Automotive Wharehouse

new pistions (boreing .030 over)

Most of the work will be done by me and a friend of mine who has rebuilt quite a few engines.

(If he was giving me a 350 I would use it, but hes only got a 305 laying around so I'm taking what I can get. any thing is better than a 2.8v6 that dont work at all.)

 

How hard are you going to be beating on the engine (stress)?

 

Reliability has to do with the components and parts in the lower end, it doesn't really matter what upper end pieces you have. The rod bolts are going weak link, then the rods...

You will be fine, your build is basically a marginally upgraded LG4. Why are you even worried about, reliability your heads will save you from ever spinning the motor high enough to do damage. That is if you don't just rev the crap out of it for the sake of breaking it for no reason.

 

Since you won't get anywhere near the power desktop dyno says with that set up you should go with a lower compression ratio so you can pump gas.

 

Okay here's the thing, rebuilding a 305 is one thing. But paying to get machine work done on a 305 (boring) is pointless. Honestly, I've seen RUNNING 350 blocks going for $100 or less even! If you are going to spend money on machine work, spend the extra $50-100 for a bare 350 block and work on that. No sense in spending a few hundred dollars on a 305 rebuild when the 350 will cost all of $50 more. Even if the 305 is free, for $50 more you could build a 350.

In any case, sounds like a nice setup. 400HP? No.. DD2k seems to have a really weird thing with roller cams putting out unrealistic amounts of power. Adds 50HP to my setup and puts me right at 400HP. With the other cam I had selected, it was saying my car should put out 450HP with roller rockers out of a naturally aspirated, 9.8:1 305.

 

Switch to flat tappet and get a more "believable" setup.

 

That was the kind of reply I was looking for. Thank you very much guys. The machine work is being done by the autoshop teacher at the votech I went to (I took the electronics course but my friend who is giving me the motor took the auto course and we are basicly saying its his car that is getting all the work done to it so we are gonna get to use the autoshops stuff for free basicly ^_^

I just wanted to make sure none of the stuff I was doing was a bad combination reliabilty wise thats all.

What would happen if I added a blower?

 

Okay nevermind, if the work is going to be free anyways, I suppose its not that big of a deal. But ya see where I'm coming from if you were spending $300-400 to get machinework done when another $50 would net you 15% power gains?

Also, yes, the flat tappet option works much better.

 

Yea I understand the reasoning on the whole 350 over the 305 debate but I have to work with what I got. Cause I'm eventually (hopefully in the next year or so) going to put a LS1, T56, and either a 9inch rear or 12bolt rear into the car. This is just to hold me over till then so I dont have to keep driving my LeSabre (and its three color color scheem... deers, trucks, fences...they dont like cars it seems...)

 

Would it be worth it to actually port and polish the heads? this is a TPI 305 that were converting to carb for simplicty sake (that and my friend sold the TPI setup to some one else we know, hes using it to build a truck 350 or somthing)

 

since you are getting the machine work done to your 305 block for free, i'd imagine that you could get a light port job done to your heads as well. It never hurts, espescially if you're going to slap those heads on there either way. Those heads need all the help they can get heh.

 

Theres no reason to even believe or think that there would relibilty issues if the motor is assembled correctly. You are not modding the motor a whole lot, just a couple basics that will boost the power a little. Your probably look at 200hp or so. Now if you were gonna spin the motor high for some reason then yes there would be problems. But since its just a stock rebuild with a couple of mild boltons no.

 

Cool. Now what about that blower :lol (i'm kidding , at least for the 305, the LS1 will get a twin screw of some time...) but thats a good ways away..

 

Yeah since your getting a good deal go ahead and keep the 305, with that roller cam, minor porting on those tpi heads and you want a 1.5 exhuast valve not 1.6 because of the small bore on the 305,I also suggest a performer RPM intake instead, the holley carb, and a full exhaust I see no reason why you couldnt make around 260 or so hp and have a fun daily driver. Good Luck.

 

260hp? RWHP? or Flywheel?

I believe my LG4 came with about 155HP (to the wheels) advertised (in the berlinetta for '86) I dont see him gaining 105RWHP from that, 60RWHP sounds about right though. And a bunch more torque (aka f-body crack)

 

The performoer RPMs mounting holes would have to be drilled out or somthing, this is an 88 305 with center bolt heads. I already ordered the holley intanke any ways.

Preaty much this will be my daily driver with some "street" races every now and then (not many cause its the rainy season in my part of missouri right now, then its winter for freakin 9 months) I want to be able to at least keep up with a stock LT1 (from 94-up vintage, cause theres this chick around here that thinks her 95 Z28 is the fastest car in town, even though my budyies Iroc ownes her every time (modded L98 I'm not sure what he did to it but its go some really great power) Same guy thats helping me do the rebuild.

 

LG4 came with 155HP and 245TQ at the FLYWHEEL with 2.73 gears and an auto in the '86 Berlinetta. Assume a 15% drivetrain loss (being a tad bit optimistic I belive), that puts you at 132ish RWHP.

The 260HP number above was flywheel I'm pretty sure. Remember he's rebuilding the motor, so the compression will be considerably better than that of the LG4, and its a roller block with the best factory 305 heads there are (possibly ported as well). New intake, carb, etc.

EDIT: Actually the '86 LG4 had a 9.5:1 CR unlike the older 8.x ones.

 

Actually engine now a days and starting after 1973 are measure net power at the output shaft of the transmission IIRC, with all the accessories, smog junk, and all stock parts (intake, exhaust...).

 

No, they measure before the transmission.

The LS1 cars with a manual put down about 10-15 more rwhp than the automatic cars.

They just measure with all accessories on the engine, but no transmission. Autos have a lot of rotating mass and the power has to get transferred through a hydraulic system instead of a lighter-weight mechanical system. Typical drivetrain losses seem to be around 18% or so with an auto and 12-14% with a manual.

The advertised HP numbers are never RWHP unless the manufacturer significantly under-rated the car.

 

Yes you are correct, i went to the source the SAE J1349 standard.
I couldn't remember exactly where it was measured, there are so many conflicting statements, even from reliable sources on this subject. Some sources say net is RWHP, others say transmission ouput shaft, and others are correct, flywheel hp with everything running.

SAE Net Horspower
In 1972, American manufacturers phased in SAE net horsepower. This is the standard on which current American ratings are based. This rating is measured at the flywheel, on an engine dyno, but the engine is tested with all accessories installed, including a full exhaust system, all pumps, the alternator, the starter, and emissions controls. Both SAE net and SAE gross horsepower test procedures are documented in Society of Automotive Engineers standard J1349. Because SAE net is so common, this is the standard we will use to compare all others.

 

Acording to https://www.thirdgen.org/newdesign/tech/techdb.shtml
the engine I'm working with is an LB9 that started life with 195 net HP and 295 net TQ. At least when it had the TPI setup. the carb and intake I'm gonna run with an upgraded compression ratio shortie headers with a 3inch exhaust and a new cam with a .030 over bore and ported heads (maybe I'm not completly sure if the autoshop at the school actually has the stuff or experiance to do it, I do know for a fact that they can overbore with out a problem though.)

So is 260 net HP after my mods probably what I'll end up seeing? and I'm thinking about 320TQ?

 

Yeah when I said 260 hp I meant at the flywheel. And although 260 hp isnt a ton of power with a little more than 300 tq youll have a fun daily driver.

 

i stand corrected then. i could have sworn that the list on this site that had the power outputs for the engine/years was rear wheel hp. Sorry about that.

 

considering my bird has a 3.42 final drive ration ^_~ I'll probably be happy for now. (who ever stays happy with what they got?)