I am getting alot closer to committing to a stroker 305 (yes I know a 383 is better, bigger, hotter, faster...). I made an offer on a 400 crank this weekend and am talking to engine shops about doing the work. Scoping out heads as well.

Are there any lessons any of you stroker guys can warn me of in advance ? Rod combos ? Bearings, how about rear seal and harmonic balancer ? Weird ECM happenings, etc..

thx,
RP.

 

plan for it to cost 2 time what you bugetted for!!!!!!

what is you planed displacement?
who's doing your build up for you?
are you going to use your block that in your car now?
can you even put a 400 crank into a 305(for some reasion i did not think you could)

 

It can be done, But really not worth it. The cost of stroking a 305 is about the same as putting a lightly modded 350 with lots of crome on it. in your car...

Oh BTW. If you're thinking a stroked 305 is the same as a 327. Um , yeah, You're wrong. sorry...

 

Palric , I think it's kinda cool you want something different I'm not sure about why you want to go smaller(then350) but it will be unique when you get it done.
Your best bet would be to do a search on engine/ machine shop's that build primarily for circle track racing. Then check their websites for different rod/stroke combo's.The reason I suggest this is that a lot of the different sanctioning bodies have weight to cubic inch rules i.e bigger c.i engine= heavier car smaller c.i engine=lighter car.As an example a fellow I used to work for had a destroked 327 (approx306 c.i)in his corvette bodied late model SC that allowed him to be 200# lighter then some of the other guy's in the class running at the 357c.i limit.
Good luck with the project...SR
PS I like the idea of stroking the other direction ,there is a guy on the "power adder board" that is running a stroked 427 c.i SMALL block (he's adding a twin turbo setup) he's expecting 1200 hp with his setup.....:hail:

 

The displacement will be 328.7cid the exact displacement of a 327 is 326.7, thats pretty close if you ask me..

Rod size depends on your purpose for the engine... I htink short rods would be more durable... I have yet to understand the theory behind rod length

 

i think what Mr Jordan means is that a stroked 305 will not behave like a 327. ie the stroked 305 will be a much different engine and have different performance characteristics than a 327.

the 327 has a 4 inch bore and 3.25 inch stroke, where as a 305 has a 3.736 inch bore and a 3.48 inch stroke, and i assuming that a stroked 305 with a 400 crank will have a stroke of 3.75 inches

 

yeah.. this is true... but it'll be an almost square engine... which is a good thing usually

 

thats true, it will be almost a square engine. but it does have a small bore, which limits breathing. however, it will be much faster than my LG4. heheh

 

Mr. Jordan -- 305 stroker not worth it ? I know it will cost more than a 350 but at this point in time I am simply interested in building something different. I checked out a 302, cool but not quite what I am looking for. Checked out a 400, too much power for a t-roofed car (without big mods to strengthen it). 350s are great but everyone has one.

Hey TriggerGTA -- I'll bet it costs alot more than I planned on. Don't they always ? Thats ok as long as I get alot more fun out of it than I planned on (ha,ha).

Snowracer -- Interesting insights into configurations. I haven't thought out the rod piece yet. Chances are this thing will get expensive and rods will be a major hurt point. I will probably keep the 305 heads with 1.92 and 1.6 valves installed over factory. Probably keep the same cam (203/208/.429/.431) as well.

There is a guy on the BIG board who has a stroked 305 using LS1 rods -- not sure how this works but am e-mailing him for details. I think he used an Eagle crankshaft which would be OEM 400 style. The car (IROC) is heavily mod'd and he does 11.86 or so says his sig.

Too much money ? Maybe. Too much engine work ? Maybe. Just checking out the options. That is what I like about the SBC -- there are a bajillion options for building a small block.

thx for your comments,
RP.

 

palric.. you and I think on the same wave length.. I am glad you aren't building the 302, cause now I can do it, and not be told I am copying you.. hehe... the stroker 305 will give some interesting power numbers... I wouldn't throw the factory cam back in though... and make it a roller engine, they run much nicer

 

"I wouldn't throw the factory cam back in though... and make it a roller engine, they run much nicer"
--------------------------------------------------------------------------------
- Hey nblanchard,aren't the late 305's factory roller motor's ? Just wondering, I was sure I read that somewhere.
- Palric, Are you planning any head work?,header's? If so you really might want to think about a different cam or at the least going to a higher ratio rocker (i.e 1.6 roller rocker's) I'm not sure the exact conversion ratio difference in lift between the 1.5 to 1.6 ,but i'm sure it would still leave you under .500 total lift likely allowing you to use stock single spring's(or fairly inexpesive performance spring's) That single change would result in a big boost in breathing ability for the engine. Just a thought........SR

 

The late 305's are roller lifters... but not roller rockers...

 

Hey Snowracer, the factory cam is a roller and as far as I know is the same profile as the '91-'92 L98 which also shares the same vintage Corvette profile -- they are all one cam.

I suppose what made up my mind on the cam was the GM Marine Master engine making 330hp and 385lbs torque out of a cam with less duration than mine. The Ramjet has 208 degrees on the intake and about .500 lift making 385hp and 400lbs torque. I am convinced the factory grinds can make alot of power just have to have the rest of the system designed to take advantage of it.

The 1.6rrs are a good idea. It is arguable that a stroker motor will want to make more torque per hp than a non-stroker motor and that being the case will require more intake (cam) duration to take advantage of the improved torque characteristics of the motor over say, a 327 (the stroker will be about 334ci). So it may make sense to have more fuel available at lower rpms, eg: more duration on the intake side which would mean buying a new cam. All that said, the bottom line is I want to keep the stock TPI and stock cam if possible.

I had planned on keeping the 305 heads but improving their flow thru 3 angle grind, some bowl and porting work and 1.92/1.6 valves. I have a connection that will make this part relatively inexpensive.

Eventually I want to build 'the right' exhaust system but that is going to cost ALOT of money so will be last on my list. It should be done sooner seeing as sbc's respond so well to exhaust mods but I only have so much in the budget.

thx for your comments,
RP.

 

Hey Nathan I still want the 302 but it would mean a mini-ram and 6-speed are mandatory. Mini-ram to pull the rpms and 6-speed to take the power. It would be far more expensive for (standard) than you (auto) so I look forward to seeing how yours turns out.
Pretty simple mod for you as you already have a 4 inch bore -- crank and rods have to be replaced ? Intake work ? What do you have planned ?

The stroker 305 works well with the TPI (IMHO). Lower rpm threshold and a power band that is TPI friendly. Figured if I couldn't do the 302 then a 334 instead eh ?

RP.

 

The stock roller cam is an excellant Torque cam and will work well in your application especially if you do decide to go w/1.6 rocker's as far as the other two engine combo's you are using as H/P comparison's the Marine Master #'s are arrived at w/free flow exhaust and a dual plane/carb combo and the ramjet is of course w/ it's own design intake.
I too plan to stick with the stock T.P.I but for a more pedestrian reason ,I just think it's an awesome looking engine.
Cam selection is an art, your right about Gm doing a fairly good job of matching part's. I have had some good and some horrible luck when picking profile's.
I can't wait to see how your combination work's out,if you go ahead with it............Later...SR

 

Some of you guys have been reading to many magazines. No matter what you do, the 305 block's max bore diameter is going to limit the breathing capabilties of that "327".

 

Palric... I still believe a TPI system will breath... I don't understand why it wouldn't. And I don't think I am using my stock L98 block... I will probably get a 4-bolt main block, and build it with that.

 

My stroker has got to be the best out of 4 engines that i've built/had built. Excellent motor for a street driven car(as you've heard, lots of torque way down low in the RPM band)

335 is going to be neat, but just so ya know, being different hurts the wallet! Do what you can with what you have & have fun, dont do it for anyone else!

Good Luck

 

Hey Nathan it is April 25th and snowing in Kitchener. Can you beleive it ?

I had a long chat with a guy at TPIS then another guy at an engine shop. The TPIS guy handed me the usual "why the 302 won't work with stock TPI" routine but did make a pretty good argument for the mini-ram. I am mulling it over.

For the record I don't have any facts on whether the TPI will work at very high rpms or not with a 302 or a stroked motor ? I have never tried it before and haven't read accounts of anyone who has. The only 350 I've ever built was more for torque than hp.

If you have some info along this line I sure would like to read it though. It may get down to some physical laws of this-or-that which baffle my brains and I'll probably end up just like everyone else with a 350. Go figure.

RP.

 

Palric.... the only physical law I can see that relates to air intake.. is air velocity.. since TPI has long tube runners, this will increase velocity a lot quicker (low RPM's) thus the tremendous torque at low RPM... but what I fail to see, is why long tube runners apparently stop working at higher RPM's.... The mustang 5.0L setup has just as long intake runners.... and its a 302... so, why it won't work.. beats the heck out of me... it seems that I repaeat myself everytime... LOL.. but no one has given me a good explanation. I am bad like that... I need solid proof, sceintific proof, or Dyno proof.

 

TPI is based on a basic principle called inertial supercharging. It involves resonance waves from the closing of the valves that physically accelerate the incoming air charge. From what I understand, at high RPM's, these resonance waves start to overlap. This can also be caused by to much cam. When this happens, it's called intake reversion.

Palric, take anything that is said by anyone at TPIS with a grain of salt. That place is out to sell you stuff first and help you second. Before you do anything that involves leaving large sums of money at a machine shop, read John Lingenfelter's book. It was one of the best purchases I have ever made that pertain to my car. I built the engine in my GTA using his philosophies and theories and if you ask me or anyone that has ridden in it.........it works pretty well

 

I have Lingenfelters catalogue.... and what I find interesting is, that the lingenfelter 1000CFM TPI system uses similar design runners and base... but with a huge plenum (which I believe you have )... If I am not mistaken, Lingenfelter has explained that the huge plenum acts as a "Storage Tank" for air... so when you need extra air... its sitting right there in the plenum waiting.

Now.. AcceldZ... can't you simply use better heads to get rid of those "resonance waves"? You said they are cause by the valves or something... I always thought, theoretically, that the L98 heads were the shortcoming of these engines, I read that in a performance magazine that did a cylinder head comparison.

Right now... my engine want to rev a little more past the redline, so I don't think its the TPI system itself that limits you... its those nasty heads. Remind you... large tube runners and better intake base is a must. I believe it will work... And I will prove it one of these days. I want to do the 302 set-up just to prove people wroing... or to show myself why it won't work.

 

ok i have to agree with acceld z on this one. Read Lingenfelters book it is very very good and will explaine almost every thing you need to know.

Now lets not forget what TPI stands for. Tuned port. the runner length is tuned for torque. the air that enters the runners is compressed causing something like a shock wave that is tuned for lower RPM. thats why when you change the base or the runners to larger diamiter ones you change the torque cerve and when you shorten the runners you add HP. you are retuning it by changing the wave length of the air being comperssed in the runners

nate, lingenfelter 1000CFM TPI system also has very short runners with larger diamiter. using his sys. you will give up some low end torque for more HP at a higher RPM. he even said it in his book.

also lets not forget that the TPI was first designed for the 305. i dont think there would be a problem using it on a stroked 305 as long as you did not plan on making lots of HP high in the RPM band. if you want a high reving engine. the mini ram or others like it would be the way to go.

High RPM,HP= shorter runners

 

Still raises the question of why the Mustang 5.0L rev so much with just as long intake runners

 

how long are the stangs? how much bigger are they in diamiter?
the stangs also have the air enter in the base at the center and dont travel all the way acrose the intake also. I dont know for sure but i think that they are shorter.

 

You pretty much hit the nail on the head Nathan. I am convinced that the Chev 302 would be a great performer even with a stock TPI.

Here is what I know about the 87-92 Ford 302 (5.0) Mustangs. They have an intake charging system of roughly equal length to the GM TPI. The Ford 302 heads are much poorer performers than the Chev LB9 and L98 heads. Ours come with 1.82/1.5 (LB9) or 1.92/1.5 (L98) while their's came with 1.72 intake and 1.5 exhaust valves. The biggest difference that I noticed is the cam. The Ford factory 302 cam has duration numbers wayyyyyy larger than the TPI motors. Typically in the mid teens I think they were 214i/224o degrees @.050. The lift with the factory 1.6 rockers is around .480. Furthermore, the 5.0 came with factory style headers to free-flow style exhaust, ours came with exhaust logs collecting into highly restrictive exhaust.

Interesting eh ? So the Ford factory cam specs are in the range that we call 'mild street'. The 5.0 factory exhaust is respectfully, far better than the 82-92 f-bodies. I can always identify a 5.0 Mustang from the growl that it's exhaust makes. FYI: the Ford 5.0 T-5 Borg/Warner tranny has a lower 1st gear than our T-5 as well.

Now when we talk about Ford factory 5.0 302s (3x4 geometry) making power, being quick, etc, there is obviously alot more to it than just the FI system. Moreover Ford's 5.0 FI system is not a magical black box. In fact if you look to Edelbrock a common upgrade available for Ford 5.0s is their FI intake system package. This solves for the 5.0 enthusiast the same problem that us TPI guys are trying to solve -- namely, how to get more air in and move the torque curve up while increasing hp. What I am trying to say is this -- the Ford 5.0 FI system works equally with the GM TPI. I do not believe for a minute the factory 5.0 is any better than our TPI (just ask some 5.0 guys if they would like to mod their intake system !) and in fact it has limitations as well.

To me the difference with the Ford 5.0 lays in the cam, ECM and exhaust system matched with a quick revving motor. As a system it works well together and is well matched. I see no reason why a Chev 302 (3x4 config) with TPI would perform any worse than the Ford 302 providing you matched the system in a similar fashion, eg: the right cam, the right ECM mods and the right exhaust.

Well I expect to hear from you guys on this.

thx for the comments,
RP.

 

Yeah... I am pretty much in the same vote as you... also, doesn't the 5.0L HO engines have roller lifters and rockers? I believe that the intake system on our cars is not the culprit... it has to be the cam duration and lack of free flowing exhaust... HECK, I gained a full second on the 1/4 mile just with my exhaust system, and THAT was with a BUMMED ECU!!!

 

what heads do you plan on using for this 305??AFAIK Only heads that will work without major work are the 305 S/R torquers and the vette aluminum heads.There are millions of 305s out there..want to be different put a big block,a TTA motor,a 4.3,pontiac or olds motor in there..Spend the $300 on a 350 core instead of the $500 machine work and parts and youll have a combo with more power,more potential and with less guesswork AND THEN BUY 305 badges

just my opinion

Daz

 

"Ours come with 1.82/1.5 (LB9) or 1.92/1.5 (L98) while their's came with 1.72 intake and 1.5 exhaust valves. "

BIGGER is not always better.

Mustangs exhaust is better with out a doubt.

this is what i see in my engine after my mods. Even with a new cam valve work and rollers every thing it still does not like to rev over 5000. i have an amazing pull from 2000- 4500 then it fells like it falls off from there. i will have to see for sure when i get it onto the dyno. but i have to ask my self when do i need to be up there?

Parlic i still think your idea will work just not as well as it would if you used a mini ram. But how high are you planing to rev it to?

daz "Spend the $300 on a 350 core instead of the $500 machine work and parts"

to spend $300 a 350 core you will still need to have checked out for cracks. as well as all the machine work. other wise you would be just gambling with your engine

one last question Palric what is your goal for this engine you want to build?

 

With a 350 you save yourself clearancing of the block,and shortening of the one bolt of the rod end..You still need to sonic/magnaflux test the old 305 anyway..What about the work on the heads and the "more expensive than a 350" pistons..Less power for more money doesnt make sense to me especially if its only to brag that you have 200 cc's less of a motor..



Daz

 

Somemore '87-'92 5.0 Mustang trivia:
The 5.0 used a roller cam after '87 and roller lifters after '89. By '90 they had a fully rollerized valve-train. Interesting considering GM was the first to introduce the roller cam to mass produced vehicles (fall of 1984).

It was common knowledge back in the '80s that Ford purposely designed and built the 5.0 with the specific purpose of beating the Camaro in a straight line. They (Ford) even made system design choices for the 5.0 that they knew would (unfortunately) keep them out of stock or street modified SCCA and Trans Am racing but would keep the car lighter on the street and faster than the majority of Camaros.

Back in the 3rd gen days there were some 38 different Camaros and Firebirds that you could buy. There were 5 Mustangs that Ford offered, two of which would beat almost every f-body built. You have to hand it to GM -- they learned the lesson by the 4th gen where you have TWO basic options, a go fast V8 and an insurance friendly V6. Just like Ford in the '80s....

Nathan, the diff between the Ford 5.0 and my 5.0 (LB9) is more than just intake and free flowing exhaust however my factory number in the 1/4 is 14.65 which is very, very close to the '91 LX 5.0 numbers. If I put a cam of similar profile to the 5.0's in my 305 and did a decent job on the exhaust I would probably be running in the 14.10 to 14.20 range. If I swapped out the block for a 302 but kept everything else I think I would be in the 13.99 range -- just like my buddies lightly modified '89 5.0 LX. I know it is hard to compare apples to oranges. Keep in mind my '91 Formula weighs in at 3250 pounds which is about 200-300 pounds lighter than an IROC or GTA of similar vintage. My friend's '89 5.0 weighs between 3150 and 3250 pounds (can't remember exact number).

Well I suppose the only way to find out the facts on a 302 TPI is to build one eh ? As far as I know there is only one guy on the BIG board who has a 302 TPI. I posted about the 302 TPI and after I got all kinds of posts about why it would be no good this guy shows up and raves about how he did it and loves his setup... go figure eh ?

RP.

 

The heads are always the problem with the 305 eh ? I don't know what heads -- figured I'd have my stockers 3-angled and sized to 1.92 and 1.6 and hope the the best ?

I keep drifting towards the 4 inch bore just because of the head question and that always leads to the same sensible 350 upgrade.

RP.

 

Agreed, bigger valves is not always better -- you have to have the a system that is matched to flow as well and that means intake and exhaust.

I think that you would be amazed at what a set of headers to a free flow exhaust would do for your setup. I did it before and was really amazed at what it did for my top-end.

The goal ? Good question. My 305 is low mileage so I am in no hurry to replace it although I am getting tired of running out of power at 5000rpm so this winter a swap is in order.

The first goal would be a freer revving engine, probably pulling strong to 6k but not with so much torque that it destroys my T5 which has a practical limit of around 325 lbs torque. So I'd say around 300hp and less than 350lbs torque peak. This would be pretty easy to do with a 350 eh ?

thx,
RP.

 

Maybe I should also point out that a mid 13 second 305 is not impossible if not easy on paper.The vette heads would be your best bet since the weight savings always help...My biggest gripe for starting with a 305 is the potential..Risk of oversimplifying..305's 12.9 or slower..350's 11's or slower..more potential and power for $300 more
IMO

I guess bottom line is what you want to do..I just hate it when a "worked" thirdgen lose to a stock 4th gen or even worse a stock new sedan..

Daz

 

"The first goal would be a freer revving engine, probably pulling strong to 6k"

i still think you would be better of with a mini ram. but make me a lire. i would even love to help you do it. and i cant wait to drive it

btw headers are next on the list after new breaks(i seem to be using alot more latly )

 

Hey TriggerGTA, I hear you on the mini-ram. Great power increase and the fuel h/w is exposed (unlike) my TPI which makes engine work easier.

I don't think I'm ready to give up on the TPI yet. I am still talking to the guy with the 400 crank and have to make up my mind soon. Tough call -- the 350 is so easy just find a block and away you go.

The mini-ram is not really an option with the 305, maybe when it is stroked ? I've heard very successful stories about the mini-ram on a 350.

I'm out of town till the end of this week (May 3rd). How about we get together before the GB long weekend ? Have you detailed your car yet ? I've got some stuff that might help. Clean 'em up abit before everyone meets.

About the headers, it used to be the header manufacturing companies often use setups like your GTA to generate numbers they then used to advertise their before and after tests. Take a built 350, put restrictive exhaust on it and pull 290hp on the dyno. Put on a full header/free-flow setup and pull 350hp on the dyno. Used to see this all the time in fact my Small Block Chevy book has an example where they gain literally 100hp over stock which tells you how painfully restrictive the 1981 Z28 350 exhaust was.

If you apply the lessons from their tests to your setup you could reasonably conclude that you might be looking at a 40-50-60 hp gain by switching to headers and a free flow exhaust. This because you would now be letting your mod'd engine work optimally through an improved exhaust. I on the other hand could put headers on and see an 18-20hp gain.

I think Nathan said he gained a full second going to low restriction without headers. If you are making a hp per cube you should be in the 13.8 range for the 1/4.

Hmmm... forgot the ECM. Your ECM will have to know about the mods -- I'll bet AcceldZ has some facts on best way to deal with this. Now that I mention it my ECM will have to know about the stroker motor... I think I'll start a thread on that.

Hey it isn't snowing in Vancouver (I am here all week). It was snowing in Kitchener when I left. Driving here sucks. Too much traffic and screwed up roads. Seen a few 3rd gens already -- daily drivers year round for these guys HA !

adious,
RP.

 

"I'm out of town till the end of this week (May 3rd). How about we get together before the GB long weekend ? Have you detailed your car yet ? I've got some stuff that might help. Clean 'em up abit before everyone meets"

sound good. i also have John Lingenfelter book for you to read

BTW may 11 the TO fbody is not at ST Tomas. there was a misprint in the flyer it is on the 25th. i am thinking we should go down then instead.

 

Hey palric... yeah, I did shave a full second off with an exhaust system.. but I don't have 350 horse YET I am probably pulling in the area of 250 at the crank (i could be wrong in that guesstimate). I'll meet up with you guys whenever.. just let me know when and where in good notice. The engine bay on my car still dirty... and got to fill some stone chips in and buff yet... but its still looking good

 

Looking forward to reading the LPE book. I am on for the 25th seeing as I don't think I'll be able to race on the 24 long weekend.

RP.