I am not sure if this is the correct place to post this or not.

BUT

I see lots of things about how well a 350 stock bottom nd is but I am wondering how fast you can spin a stock LB9. OR at least what it can handle as far as HP.

Please dont tell me how I should just get a 350.. I know that but I also know that anything I do to a 305 I can also put on a 350/383/400/454sb and do even better.

If this needs to be moved please email me and tell me where you put it.

Thanks for your help.

 

You should just get a 350.



I dont see any reasons you cant push a 305 as far as a 350 on the HP scale. Look up Willie and tell me thats not enough speed for you.

 

So you think the stock bottom end of the 305 can handle 6,000 RPM and about 325 HP?

How fast do you think you can safely spin a stock bottom end?

 

I have goodies on my LB9, and I usually spin it up to 5500.

Now that I have nitrous(75hp shot), I am sure that I am making 325 engine hp.
Gone thru 2 bottles, and no problems yet!

As for the 6000rpm,
1. Why? TPI's don't make power up there anyway.(Unless they are ported and have better heads)

2. I don't know if the factory valve springs would allow it anyway(start to float, and not close)

LB9GTA

 

Well they would if you changed all that. I am thinking about doing a Cheap make over to it until next March when I have time to change over to a 454 SB's..

I am thinking HSR a 230 cam with around .500 lift. As well as porting the heads and adding new springs. Also 1.6 rockers.

Then I can use all the parts on the 454 SB next March and still have fun with the 305. I should also get pretty good at burning PROM's with the 305.

As far as cost it is really not that big a deal. Time is my problem.. Kinda weird,, When I was working for other people I had lots of free time and no money. Now I run my own business and have lots of money but no free time. Funny world we live in..

 

If you changed the springs that would be pointless unless you changed the heads and such as well($$).

LB9GTA

 

So I cant port the stock heads enough.. That is a horse of a different color. I did not think about that problem. I figured I would just port the **** out of them and be fine. Are they really that bad??

Now I guess it's back to the drawing board..

 

If you are going to go thru the trouble of porting stock heads, go and get a set of Corvette L-98 aluminum heads(off of ebay for about $500-600US)

As for the springs, aren't they about $200(comp cam? brand)

Alot of work for a 305 when you are going to do the 454.(Do you have the block already?)

If not, do a 383. 350 block(everything almost off your 305 will switch over) That is what i plan to do (the cam, headers, afpr, ) will switch over.
I don't know that everything u have will switch to the 454

LB9GTA

 

No I have not bought it yet. The one I am looking at is http://www.jegs.com/cgi-bin/ncommerc...96&prmenbr=361 The last one. I will be buying heads for it then also.

I did not think all 350 heads would work on a 305?? If a set of aluminum covet heads will go that route.

I bought this STUPID book called Chevrolet Small Block parts interchange guide but it does not say one thing about what parts will work on what engine??? It has a bunch of generic descriptions of how things work and casting #'s. At least I have a complete list of all the GM SB casting #'s at my finger tips now.

Anyway I thought SOME 350 heads would have problems with the valve hitting the small bore of a 305.

 

The vette heads(aluminum) will work on 350's and 305's.

LB9GTA

 

I just have to ask because I dont understand.

Most of the aftermarket heads say they will not work on anything smaller than a 4" bore unless you have less than 450 valve lift. I would think that would hold true with all 350 heads.

What am I missing here. Do the after market guys actually move the valves farther apart?

BTW. Thanks for helping out the new guy.. If you ever need help with a MOPAR product let me know that is where most of my knowledge is. I just have always wanted to build a TPI car.

 

Well by reading this info: http://www.flatlanderracing.com/afr180cc.html

The part that reads.

I can see where the problem is. As long as you run the smaller valves you will be fine with them in a 305..

 

I can get her to about 5600rpm in my Roc. The stock heads being ported are pointless without the intake and runners being changed(not truly pointless but better with a full upgrade).
I love my LB9, sure it is not as fast as a L98 when stock or modded but who cares have fun with what you brung!!!

 

Where you spin the motor is based ion the intake...long runner TPI you might get a little over 5000 grand...a LB9 should handle that...just remember these motors are getting old..the bearings/rings ect.have been through alot...the 305's are workhorses..I know..I have one and it has run good for me for a long time...but you start adding alot of power on a 15+ year old bottomend...well you just don't know.
Which is why people just suggest a 350 since a rebuild is going to be needed sooner or later its not much more for a 350.

I think a heads/cam 305 TPi could run very decent set up right...
port the stock heads or get a set of aluminum L98's...something around the ZZ9 spec cam...would be a very solid performer with all the other usual mods...

 

I have a roller 305 that I spin to 6500 rpms

stock bottom ent 750 cfm carb

later

and

GB

riuck