OC305RS

WANTED TO KNOW IF IT IS POSSIBLE TO BORE AND STROKE A 305 UP TO 327 CUBIC INCHES..?
I KNOW WITH 400 CRANK AND A .030 OVERBORE YOU GET 334 CUBIC INCHES....BUT, WHAT STROKE WOULD CALCULATE TO 327 INCHES? AND I WANTED TO RETAIN MY SMOG...IS THIS POSSIBLE?
WITH SMOG HEADDERS? AND A THROTTLE BODY?
ANY INFO WOULD HELP...THANKS

Inwo

It's possible but a collosal waste of money.

camaro6spd

Yes but No. The 327 is a 4" bore and a short Stroke....The 305 is a small bore and long stroke. The crank would fit but you can't bore the 305 out to 4"

8Mike9

I'm assuming you want to make a 327 as GM did in the '60's? If so, the 305 block is not the one to use. I suppose with an offset ground crank, the cubes would be possible, but not worthwhile just to say you have a 327.

What you want to do is look for a 350 block (4inch bore) and use a 3.25inch stroke crank to come out as a '60's 327 cu.in. displacement.

five7kid

iTrader: (14)

There is one other option - stroke the 305 with a 400 crank after boring out the block by .030". Now you'll have a 334.

Considered it, decided against it. Too much money for too little gain. When I approached a local speed shop about doing the boring on my 305 for such a 334, he told me he'd sell me a roller cam 350 block, stroke it to 383, and it would still cost no more than going 334 with my block.

You're better off spending your money on a 350. In fact, you're better off spending your money on a 350 than simply rebuilding your 305. I'm saying that even though I've obviously put some other money into my 305 - just didn't do anything involving the crank or pistons.

Now, if you have a 327 block sitting around, that's a whole different story...

P.S.: The majority of 327 cranks would NOT fit in a 305.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

[This message has been edited by five7kid (edited December 04, 2001).]

AlkyIROC

Most 327 blocks were an 0010 casting the same as many 350 blocks.

You just need to find the shorter stroke crank.

five7kid

iTrader: (14)

Can't agree with that, if you're saying the blocks themselves were the same. Most 327 blocks were small journal ('62-'67), only '68 & '69's were large journal, and by then they were being replaced with 307's and 350's so not nearly as many were made those two years.

Now, a 350 block (2-piece rear main crank) with a 307 (most plentiful) or 327 large journal crank & pistons - you have a 327, just like that.

DM91RS

Just curious, how much can a 305 bore be safely increased and what C.I. would this make the motor?

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91 RS 5.0 TBI....LT4 cam....Edelbrock headers....3"Dynomax exhaust....5spd.... 3.08.....Ultimate tbi....afpr...ZR 255-50's...Koni's

[This message has been edited by DM91RS (edited December 06, 2001).]

DUGMAZE

I have a 292 C.I.

.030 over 305
327 crank

camaro6spd

What kind of power does that engine make?
292

Tas

hard to belive you found pistons to do that. I think you're pulling our leg



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-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

LastHopeRS

enginekits.com sells the stroker kit for the 305 to 334/335, and they claim F.I. could see gains of up to 115 HP. not too shabby. it was used on project: silverstreak

Damon

Don't do this project. The largest safe overbore for a 305 is MAYBE about .060" which will get you up to about 315ci.

Shoving a shorter stroke into a 305 is gonna cost you HP and a bucket load of torque, which is already in short supply in a motor this small.

Shoving a longer stroke in a 305 is not gonna build much HP, but may increase low-mid torque a fair bit.

The problem with the 305 is that the bore is just too damned small and it doesn't give much room for the valves at the top of the cylinder. THerefore it's tough to make a 305 breathe well. And that's why you don't see much in the way of aftermarket cylinder heads for the 305.

RB83L69

You're not going to get 115 HP by adding 20 cubic inches to a 305. I'm sorry, but that's pure unadulterated bull droppings. You can't possibly take a 200 HP 305 CID motor, .65 HP per cu in, and get 5 HP per cu in out of those extra ones. Somehow I just don't think so. You'd be beyond lucky to get 20 HP extra out of just the stroke. In fact, in the majority of builds, I'd be surprised if the extra stroke by itself was worth 10 HP. That is, if you took 2 otherwise identical motors, one with the 3.48" stroke crank and one with the 3.76" kit in it, the difference will be less than 10 HP.

So, if the stroker kit for a 305 costs $500 and gives 10 HP, that's $50/HP; but if a 350 core costs $500 (it probably won't) and gives the usual 30 HP or so above what a similar 305 will give, that's $17/HP. You decide how much value you're going to get out of your $$$.

Now it may be that they took a 305 block, and by doing various things to it (HEADS) as well as putting that 400 crank in it, they got 115 extra HP. That's believable. But the whole problem with that is that the "stroker kit" costs more than a "borer kit", namely a 4.000" bore block, and still gives you about 20 less cu in.

I agree with Damon, it's a stupid idea to work up exotic engine combinations for a 305 block, except in very special circumstances (read: matching numbers block) only. If you're going to dig into your short block, it makes no sense whatsoever to pile $$$ on top of $$$ into a 305, with 350s as cheap and plentiful as they are. De-stroking a 305 won't make it a better motor.

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"So many Mustangs, so little time..."
ICON Motorsports

Grim Reaper

I completely agree with RB. I am currently in the middle of a build-up of my L98. I have access to a computer dyno program used by an engine builder. This program is not your typical Desktop dyno. With the correct technical specifications and flow numbers, it comes surprisingly close to the actual engine dyno readings this engine builder attains.

My actual reason for using this dyno program is to help me "predict" the VE Tables for the eprom I am burning to make a particluar engine combo run right. I have used this program in the past to help me "draft" bins for custom eproms, with good success.

When I plug in my current TPI L98 engine but with the stroke changed to make a 383, I get about another 40 lb/ft of TQ, but not a single HP over my TPI L98 350. The HP remain identical except occurs 500 rpm lower.

Well, like you, my first reaction is that it has to be that damn TPI intake. So, I then went with a "hypothetical" 350 with a Miniram, a fairly short duration HR cam (214/222 .488/.509 @ .050 w/1.5 RRs) and professionally ported 58cc Vette heads; as this is the setup I will be installing this spring.

The program predicted a healthy increase in HP with not that much of a drop in TQ from a stock L98 (due to my choice of heads and cam). The worst I lose is 22 lb/ft at peak TQ with the average TQ lose being only 15 lb/ft from 2,000-4,000 rpm. But after 4,000 rpm, my HP and TQ exceeds and continues to climb way past the TPI L98; until it's peak HP @ 6,000 rpm.

So I then took this combo and just changed the stroke of my "hypothetical" 350 Miniram to a 383; all else the same as my 350 Miniram combo. Stroking the engine resulted in the same TQ characteristics as stroking the TPI L98 to 383. I got the same 40 lb/ft increase in TQ throughout the powerband from an idle - 4,500 over my 350 Miniram combo with minimal increase in HP. My max HP only increased by 10 HP with the 383 Miniram over the 350 Miniram and occurs 500 rpm lower (5,500 vs 6,000).

So I too agree with RB. Stroking an engine (without major mods) will result in more TQ but HP will change minimally and at a lower RPM. You need other major mods (intake, heads and cam) to make major gains in HP. But not by changing stroke alone.

[This message has been edited by Glenn91L98GTA (edited December 07, 2001).]

five7kid

iTrader: (14)

You can up the power of a 155 HP LG4 by 115 without touching the shortblock. Smog legal.

FI as well, it'll just cost you more.

DUGMAZE

I'm not a good guess at HP ratings but I assume I"m in the 210-220hp range.

I get 20 miles to the gallon

everything is brand new

spent around $1000 on motor but everything is new

here's my combo:

1978 305 .030 over
completely flat top pistons
327 crank
300hp cam(where they get that name I don't know!) .401 lift
.015" GM shims
1978 305 heads 58cc 1.8 valves
10.5:1 compression
Early 80's Z28 intake
Quadrajet (love the bog)
shorty headers
glasspacks
2" true duals--no cats

This is my everyday driver and have no complaints. I run a 229 gear and can still beat stock trucks and most cars. I'm currently going to a posi, 3.73 rearend so I can see what this motor will do. My car is a little too heavy(78 Elky) so the gears will do me good.

There's alot of "can't do this on the street talk". Any small block will make good street power by removing stock items. Once I took a 3600lb Corvette, put in a 355, 292 cam, stock heads, with a 3500 stall. Everyone said the stall was too high, bull. Tell that to the Mustangs and Camaros. It was a 14 second car and did 80 in the eighth mile. With the traction I had from being 55% rear weight, I smoked some pretty fast cars on the street. From stop light to stop light is 1/8 mile. But at the strip I was the slowest. That's why I built the engine for the street, because I only go to the strip a couple times a year.


My 292 isn't a monster motor but it's in my 78 El Camino parts truck and I have my 396 Monte Carlo for the power.

ede

i have a 336 in my old car, runs great, stronger than most engine/car combos i've been in or around on the street lately.