is this the right place to post this?? I wanna build a 305 that can take out modded lt1's. How would i go about it. It would go in my 84 TA, which will have a 3.42 posi rear, and a TH-350 tranny. I already have an LT1 cam, should i dump it and go with something more radical? How radical is the LT1 cam, and how much more should i go. How bout the torque convertor? I want to have this combo ready by May. Any suggestions?

Power adders....

the only reasonable way to do that is to get a bottle..... 305s r a waste unless you have gords of money to waste when a 350 would give you more for your money due to the 45 extra cubes over a 305.

ok now that everyone has told you, that you might be wasting your money, I can now list parts to "waste" your money on.

First get your block bored .30 over and some lightweight pistons.
get your crank and rods redone, and/or get new lightweight alum rods.

Compcam XR268 or XR274
World heads and port the $hit out of them.
good single plane or stealth or RPM manifold
750dp mech secondaries
3.73 gears
and NOS.

and your choice of blower.

also it wouldn't hur to get ride of excess weight, back seats jack spare, rear carpet.

glass hood (cowl while your at it.)

And there you are a recipe for spending money.


PS with honesty now a 305 can be built to anyway it does take money, but for budget 305 it can beat stock LT1's

Your parts list is a bit old school....and BTW...aluminum rods are not a good idea for any kind of a street car...durability is an issue over the longer (more than 250-500 dragstrip passes)...

I could also suggest the Trick Flow 23 degree heads...they are a great budget item and flow great out of the box...

As for the cam...no bigger than XE268...and consider just the XE262...depends on what power levels you want...I think the XE262 would work better for at least 350 HP.

As for the carb, a 750 DP may be a bit overkill...either a 650 or a 700 DP (jetted properly of course) would work better....

Good luck

I think he can rebuild the lower end with a forged rebuild kit.
Lower compression to around 8.0:1 - 8.5:1
Supercharge it.

I imagine you could accomplish this with three or four thousand dollars if you have the right knowledge, connections, whatnot.

I also imagine that with the amount of boost you could run, due to the forged rebuild and low compression, would smoke LT1's like you want it to. If you have the extra cash to venture such a project, I would love to see more on this and what you decide to do. I appreciate N20 more than I used to, but I still lean toward more n/a and blowers or turbos.

thanks alot for the quick responces!

Actually my TA already has a 350 in it. It's got a very mild cam, Stealth manifold, 600cfm Holley, headers w/3in exhaust, and a couple of other things.

I want to build up an '88 305 i got for free from my friend's bird. I also have alot of friends with 305 third gens who get a lot of crap from 4th gen owners about their (i have a 305 in my Z28 too) "weenie" motors. I hear them say how they would kill themselves if they lost to a 305, or how they would never race again, basically crap like that.

I want to be the one that hands them thier ***! If they never race again or "kill" themselves, it's all for the better!

Sounds like you have the right attitude.

So my first build was a little on the weak side.

I would change first off the cam would be better witha XR262 as mentioned above.

Also for heads ported Alum Vette heads or AFR 180's both excellent heads.

next woudl be the low compression as above if you plan on S/C
or go with 10:1 as alum is good for it.

forged rods and pistons (if S/C'ed) otherwise just a good set of prepped 350 rods and some good pistons should do.

but good luck in handing some A$$, should be nice to make a 4th gen owner eat it, as most 3rd genners started life with only 5 liters.

Best of luck to ya


PS if you need a good receipe check out Sitting Bull, member on this site with a 305hp 305ci

Seriously though, i want to build a 305 that can get some rescect. I don't want to build something super expensive that could take out every 4th gen, (There's a guy in town with an 11 sec Formula as his daily driver) I just want something i could race a couple of times (while i work on my 350), and later on sell to one of my buddies.


I've been thinking and im going to need nitrous. Don't really want to spend to much on the heads so im going to need something to compensate.

Will this cut it, or will i need more:

.030 over forged pistons, will reworked stock crank & rods handle the power?
CompCam XR268 cam
ported 305 Torquer heads
Should i use the Stealth manifold i got, or should i get a single plane?
will a Holley 600cfm douple pumper be enough?
finally a 175 shot of nitrous

My sentimates exactly!!

I'll make sure to keep everyone posted, i'll even make a website about it. Think it would be cool.

A heavily modded 305 wil never beat a stock LT1. The only way to build a 305 which is faster then 13 sec, is a power-adder. I would suggest a supercharger.

I would melt down the 305 block and cast a new 400 block, the mod that, that way you will have a chance.

A worked 305 CAN INDEED beat a stock Lt1...

I don't think reworked stock internals would be ok with a 175 shot... I like my idea better.

True an extremely worked 305 can beat a stock LT1, which ran mid to upper 13's. It will take a lot of money and work.

But try an slightly modded LT1 and you will lose.

granted this is no where near stock and a far cry from any stock 305 block in the history of third gens, but......

305, anyone????
www.tpi305.com


this guys from my town, and hes nuts

A modded 305 CAN beat an LT1. Noone really debates that. But most people know that spending the money on a 350 goes a lot farther than just the simple fact that it has 45 extra cubes. Car craft built up an '82 LG4 with 80000 on the bottom end. they got 325 horses out of it with cheap, of the shelf parts. Vortec heads, headers, flows, XE268 cam, and a victor jr. manifold. The only thing was that they had to mill the vortecs down to increase compression. There are aluminum L98s, 081's, and 416's which are all very good starting castings that port out nicely, while at the same time they have 58cc chambers which will keep your compression up. Obviously, you could theoretically get even more out of it NA, but after that point, you really are experiencing diminishing returns. With a blower, you're blowing the doors off LS1's and the like. There' a guy on this forum who goes under the username Willie who has a blown 305 that runs 12.

Start with finding some early model 350 heads or get aftermarket 350 heads, build a 350 to match their effeciency. Now tell everyone that it's a 305 and you got it.

I had my first race tonight since the engine swap against a 4th gen convertable. Down the Freeway we rolled on about 70 and I walked away till well over 100-120. Got a couple of car lengths ahead. It seemed to gain a little but never did catch me. TPI torque Rocks !

You can get a 305 to beat those sissy LT1s all throttle no bottle. Give that little hummer to me and I'll build an engine you can zing into the stratosphere. Then you build that turbo 350 with a 9.5" 4000 RPM converter some 4.11 gears out back. Lift bars or LCA relocators. Some Nitto or comporable DRs. Take about 200lbs of crap out of the car.

BTW before I get flamed to death. This is about as assinine as make a 1.8 Honda go into the 11s. Sure you can do it, but isn't it a lot easier to do something else. I guess this is one of these principle things.

Some of you guys are missing the point of his post, he wants to build a 305 to teach 1 count 1 LT1 owner a lesson. In the mean time he WILL and DOES HAVE a 350 he is building.

So just help out with a 305 build up cause he already knows and has a 350.

your list of parts should be good, just remember some gears and good traction is also worth its weight.

Especially not with a 4" + bore.

TECH SPEC’S


ENGINE
BLOCK Bowtie 4.025” bore x 3.0” stroke-305 cu/in.

ya i was just referencing what you can do with 305 ci if you have the cash

This isn't directly aimed at you, but please stop posting this unless you inform people that the engine this guy is running isn't in any way comparable to the 305 everyone here has or has thrown in the garbage. If someone gets the idea that they can make their car this fast without changing the engine, they're going to be severely dissapointed.

yea what i would do if i were you is get the xe262 cam and put 1.6rockers on it..... so that way you have more lift than the 268 but not too much duration.

Im fairly sure they could hear the difference between a 350 and a 305. 350's sound way better and meaner.

They do?

Sounds is based upon several factors only one of which is engine size. Just to say that a 350 sounds meaner then a 305 is false and not true.

I was saying that from my experiences with my own cars, and those of friends and basically other cars i hear that in my OPINION a 350 will sound better than a 305. The 350 in my Trans Am sounds way better than the 305 in my Z28. They both have the same headers, piping and muffler. My friend's RS that has a 350 sounds similar to my 350, yet still very different than my 305 as well as my other friends' 305s.

Can you tell a difference between a ford engine and a chevy engine and the way they sound? A Ford will sound like a ford, a sound which in my OPINION sounds better than a Chevy.

The 305 has a distinctive sound to it that 99% of the time i will be able to differentiate from being a 350.


I know what you are trying to say, and i do agree with you up to a point. But from what i have seen and heard a 305 will always sound like a 305, and in my OPINION not as good as a 350.

isn't it cheaper to buy a 4th gen LT1? i sold my 1991 firebird for $6000 and paid $1900 more for a 1995 T/A. I don't regret it one bit. I'm sure you will have to spend a lot more than that to get your 305 to run with LT1's. My 1991 was lucky to hit 16.5 and i know my new T/A will run around 14.0 to 14.5 and with an intake hopefully hit 13.99 in the 1/4.
just my $.02

My friends 94 Z28(LT1) runs 15.00 All day through a six speed. 100% stock.

LOL Lets see...The car at www.305tpi.com.. how to put this.. Just because it's mathmatically a 5.0, it's still a 5.7 bow tie block. Put six inch rods in it and call it a 305 which maybe mathmatically close. I'm pretty sure if it was an event for 305's, It may not qualify. It's still telling the guy to build a 350 which is I think a good Idea.. ..

I think you need a sponcer to make a 305 do what you want but here is my Idea on how to do it...

Run NOs, Turbo or a Blower... as suggested. or whip out some serious cash....

Without a power adder, trying to get a 305 to run down a modified LT1 is a major task. If it is modified to be a runner...
You'll need exactly the right heads, ported, flowed and polished to the max. 305 heads have the valves pushed close together so heat transfer is a problem from the exhaust valve to the intake valve distrupting the air flow. Something a flow bench doesn't show.. The valve sizing is also limited because of their location. If you use 350 heads, the valves make contact with the cylinder walls ( A reason why 350tpi.com has his motor like that ). You'll need to nail the combination on the nose and then get everything you can out of it. The computer monitored and the fuel curves adjusted for a while. Be able to afford a few injector change if need after the first one or two sets..Then make a gear change that will use all the car up on a pass. Posible.. Yes.. Using a 5.0 may not be a very money effecient choice but it is possible...
Hiding a 350 as a 5.0 will not sound any different. My car came with dual cats and big exhaust. My girlfriend said it shook the house more than my flowmaster stuff does now when I back in to the gaurage. I don't know about the shake but the noise is not as loud as it is with flowmaster. I installed a 350 hiding as a 305. used a ramjet cam and the 305 heads. The diffrence wasn't worth it. I re did it, got some good heads and ported everything I could in the induction system. Cranked up the fuel pressure and put on some headers and increased lift with some roller rockers.
It still says 305 on the hood. I do have perimeter valve covers which were a earlier 305 thing too. I beat a LT1 I last night. My stock motor suprised many. It wouldn't have beat the LT1.

Here's the deal... It's a small block Chevrolet. Just as the LT1 is but it's a different generation of power plant, yet it's still a small block Chevy. Take a 5.7 and make it a 5.0. Take a 400 and make it a 372. Take a 350 and make it a 383. Whats the difference ? Not looks unless LS or LT versions...
A sh,t load of Money..... Yes..
What do you call it ? .. What ever you want.. you paid for it..

One point that hasn't been brought up, the majority of LT1s will run low 14s, so building a 305 correctly, shouldn't be too hard to take out a stock LT1.

I don't think anybody has covered this, but most aftermarket heads won't work with a 305 because they are built around a 4.0+ bore. There will be valve interference, squish area problems, and very low compression. There is only 1 choice for aftermarket 305 heads as far as i know and those are the dart sr's. they require alot of porting and still are a far cry from basic AFR's. The real reason 305's suck is the bore and stroke combo. You can build as much RPM as you want but your not going to make big power up top unless you find some one off high end stuff. Even then you have a small displacment engine with no low end and a high reving motor with no top end.

Build a 302 get a 3" crank and a 4 bolt 350 or better yet 400 block and go have some fun.

heres my idea.

put a stroker kit in the 305 making it 335ci. from powerhouse

then get your current heads reworked and have them install 1.95 valves instea of 1.84valves.
the ram jet cam
along with headers and flowmaster catback, removing the cat with a mac off road pipe
crane cams- push rods,lifters,springs, 1.6 roller tipped rockers
10:1 compression if n/a with nos
8.5:1 compression with a super charger

and get a super charger- that can be your pick lower control arms, rear panhard rod and subframe connectors would be helpful.
oh and get some drag radials, and you should have a 305 that will take out more than a stock LT1's

unfortunately it also takes out bank accounts too!! If you have cash to burn and wan't a challenge then build the 305, if you have a budget and want bang for your buck get another motor.

zackly

very true,
but he wants a 305, if u just want raw power, get a 383- thats good for 320hp, no matter what u do to it,
if u do it right u will run next to those feared ls1's

This was a couple of years ago on cylinder heads for the 305. They installed the world products..and they also installed the Twisted Flow heads for a 350 on the 305...yep..2.02 1.60 on a 305...I believe the author said they would fit but the valves would be a touch shrouded from the small bore. A 305 can be made to run ..yes..but take a 350 and apply roughly the same parts and the bigger cubed motor wins..But I still have a special place in my heart for the little engine that could..lol..Later.

305iroc...
can your friend shift? my friend has a 1994 formula (auto) with exhaust and a k&n and dry rotted bald tires and ran 14.17. I raced him once on the street (he got new tires) ,and my car is bone stock, and i pulled on him. i guess different 4th gens just don't run the same.

yea i was thinking the same thing...the dude must not know how to drive...

and that assinine comment about a 305 not beating a lt1..
yea ok buddy...hows 14.12 buddy..that sound like itll be a lt1...thats with a flowmaster a k&n and some plenum grinding...

i raced my buddies lt1 on the street (hae had on et streets i had regualr street tires)..i dropped at 2,200 and he neutral slammed it ..he got outta the whole first but i was coming by by 40 and he passed me back at 95 or so

Well that was with two people in the car. He had a lot of other stuff in the car to. With two people in my car it adds about 2-3 tenths on my 1/4 mile time. Most stock LT1's I see run at the track run high 14's-low 15's??

man what are you guys saying? a 305 can take a stock lt1 but, yes he needs some heads or at least really reworked ones to get past the flow problems of a 305 (Thats the 305 problem the small bore and shrouded valves) have the heads milled try to shoot forr 9.5-10.0 comp. maybe even bore it to help with raising your comp. and the valve shrouding (its not a big help but, it will help) then a decentt cam, int. and headders.. the internals will just allow for power adders.depending on your intake and cam you may want 3.73 gears. you should get real close with hp to a lt1 but, the gears sould push you over. the cam and int will be the big differance with this setup.

Well, Ill give you a number to shoot for, In my LT1 TA that I just dynoed I put down 300rwhp and 322torque. Get there and pass it and you should beat modded LT1's I hope you do it!

It's so lame to see people bag on a 305 because of the 305's rep as the emissions engine....

My 305 takes on stock LT1's, and I dont even have major mods done to my car!


I'd like to see what an LT1 will do to me when I put on my fully ported & polished tpi intake, heads & headers....



Look @ my time in my sig.

You're kidding...right? Stock LT1's are around 13.9-14.3.

My friend Joe has a BONE STOCK 305 TPI in his Iroc....all he has is free mods and he ran a 13.9 @ 97mph in the fall. Look up the user "SLP-IROCZ" on this board.

Forged/balanced rotating assembly, dished pistons for 8.3:1 static compression, ported TPI system, 1-3/4" headers, and two TE-52 turbos with 76mm turbines. Plumb it all together, add the fuel, and you'll beat most stock and modded LT1s, LT4s, LT5s, LS1s, LS6s, and about anything else you'll encounter along the way. Anything with a blue oval or toasted rîce falling out the tailpipes won't even be a challenge.

It should run high 13"s....

I've NEVER seen a stock LT1 six speed run high 13's EVER.

most here at fastest stock run 15 flats to low 14's depending on driver.

i can imagine an LT1 stock with slicks probably getting high 13's

If you say so...

I found a stroker kit for the 305 to turn it to a 335. Do that with some heads and what not and you can knock some LT1's off their pedastals.

I have considered this for my own ride. But I am probably going to get a 350 and build it while I continue to drive my car. Then when I am ready to I can drop in the 350 and sell off the 305.

the 60' time in my sig was the first time I had the 94 at the track...it was around 40* and nobody was getting any traction...1-2 shift I was all over the place...and the 2-3 shift was real loose...I notice your best 60' with the 305 was the same.....Best as of 11/01/02: 14.4 @ 97MPH W/ a 2.3 60 ft.
I have no doubt I can bust into the 13's on a good night...I go to the track most weekends and I see stock LT1's running 13's. Maybe the air is different here in Ne...I dont know, but I know what i see...and I'll post ya a timeslip when I do it.

I'm not calling you a liar, I am just saying round here I have never seen LT1's run low 13's stock.


My friend has 2 4th gens, a 96 LT1 auto and a 94 LT1 6 speed and we have raced time and time again, One time we raced from 0 to about 80-90 and we ran DEAD even, it was as if we weren't even moving, pretty awesome sight.

the air temp when I got my time was around 80-90 degree's.

Somebody here said to get aluminum rods. DO NOT DO IT. Especially if this is a street engine. The expansion properties of aluminum are such that unless you let it warm up to normal operating temperatures you will spin a bearing. Aluminum expands at about 1/2 the rate of steel(I think) and you would not be able to give it any gas until it completely warmed up. Also aluminum has to be check every couple thousand miles for stretch and such. So every 3,000 you would be pulling your engine apart to have the rods checked. I guess what I am trying to say is unless you have a track only all out race car don't go with aluminum.