w/FRMLA on 1/4 mi predictions

If it were me Id spray it til it blows then build something with another 50 ci +100shot. A 350 after your 335 wont thrill you imo. if youre dead set on doing it then just go for it and be happy with however it turns out sounds like youre not hoping for a whole bunch

 

Agreed. The added 30 cubes from stroking it will gain you less than a 10% power increase. Upping your jets to a 125 shot will do much more.

 

That 305 will like a 125-150 shot. Run cooler spark plugs and don't get greedy with the timing. I sprayed my 305 until I built the 383. I sold my N20 kit when I built the 421.


Reading thru this post I see a lack of experience / understanding with engines, and granted if you just started into the hobby nobody becomes "expert" overnight.

There are some great articles explain why a bigger bore engine is better.

but in simple terms is boils down to this.... HP = TQ * RPM / 5252

A bigger (bore) engine will make more TQ at any given RPM than a smaller one.

This is why the 400 beats the 350 and the 350 trumps the 305.

In retrospect I should have gotten away from SBC and went to BBC.. but that is another debate entirely. For me it was the simply that a SBC fits with ease into this chassis, a BBC not so much.

Do not fool yourself into believing a 305 can ever outperform it's big brothers when they are built equally... it simply can't

I did not create the laws of mechanics but none of us can break them.

 

It all depends on objectives honestly. Everyone seems to think that people need to have 4 digit HP 8 second cars to have fun. The car rags and Hollywood perpetuate this image. A car running low 8s in the 1/8th is a pretty damn serious machine even today.

Just because he doesn't build a 421 SB now doesn't mean he can't get value from the 305 later down the road. Figuring out what he did wrong and learning from it is probably far more important. Hell I knew a guy that ran 20 PSI on a Buick Grand National engine and made 217HP at the rear wheels. Spent 20K on the engine by the time he was done and came out less on the dyno than a stock car did! The fundamentals apply to this engine and a Ford, Pontiac, Olds, Cadillac hell even a Briggs and Stratton. The better grasp he gets on this low buck wonder the better future iterations will be. Most of the parts he has will go to a 350 and be fine on it. If he takes a step up to a monster SB like you have, he'll have to change virtually everything anyways. Some 1 5/8 headers aren't going to do the trick for a 421" motor. Doing a "4 inch bore mod" on this engine will not magically fix the flaws with his powertrain and the combo. The intake isn't fine for a 350 with his current setup, but it's not fine with the 305 either. An RPM or a Vic would be right at home on a 350 though. And even though the cubes WOULD actually help push the power band down closer to his shift points, even a 100 CID bigger 400 would probably not want to be shifted at 5500 with that cam. He'll probably make as much if not more improvement by changing the governor weights and adding an intake than he would by doing a 350 short block under what he has.

BTW, was your engine stock or did you mod it out a bunch? Do you have a thread with your 305 mods?

 

Yes, a new bigger engine is not a silver bullet. and I am not suggesting that.
You have to address the whole power train and chassis.

It took me 20 years to modify my car to this point.

So yes my headers are 1 7/8" stepped to 2" with 4" collectors. They were hand made by Lemons and cost more than my first car did! My cylinder heads (Brodix 18 degree) cost more than some crate engines.

The only things "stock" on my car are the body and interior.

And I repeat this process did not happen overnight.


I learned very early the limits of the 305 so I spent no real money on that engine.
The biggest expense was the N20 system and that IMHO is the best thing you can do to it, without a doubt. A cam swap will not get you 100-150 HP on that motor.

Better heads are a waste of time because they can only ever be used on the 305, so if you plan to go to a larger SBC later on the heads are scrap (only worth money to another 305 dreamer).

It's free advise based on real world experience you can take that for what is worth.

In the end it is your hobby, time, & money. Build what you like but don't whine about it later when your "vision" does not live up to your expectations.

in the 10s !

 

Thank you' I apologize for that' brand new to the site.
But back on topic guys I am not running stock valve springs, they were purchased for cam when I bought it. An I'm sorry if this sounds rude but iv mentioned it several times that I am not looking to compare 305/350. If u guys don't like the 305 I understand but please respect iv chosen to build it an also know my father drag races an has his whole life an again I am more then aware in every way a 350 is better but this is my street car, its a 305 an id jus like to see how fast I can make it.
Wat r ur suggestions on 350 heads? Jus mill them as much as possible to keep the compression up?

 

keep stock crank, do a forged piston and good rods. get the trickflow heads, and some sort of cam. hit it with as much nitrous as you can.

 

If you really just want to see how fast you can make the 305, then please, stop all the talk about a 335! Yes, it may still be "just a 305 block", but it's no longer "just a 305".

If we can get over that hurdle, then Diggler has said all you need to know.

 

If you break it down i really have not done that much to the car, heads are stock however i hoged them out and put in 1.94 intake valve, also milled them .010. I am running a comp cam, forget the part number but specs are .510/.520 lift, .232/.236 duration @.050 110 lope sep. I converted it to carb and am running a holley 650 dp carb, also shorty headers and flowmaster exhaust. Out back i have a posi 3.73.

Those are pretty much all my performance mods. Plus the 100 shot plate.
I know you guys are all ragging on my 305 and making the assumption that i am uneducated, BUT I havnt been just tossing parts at this car, i do know and understand what it take to build an engine, and again i am NOT making a drag car. I understand its limits. In fact I have a 350 on my engine stand I am building for another 3rd gen that will be my drag car, but like i have said this is my street car that I bring to the track on the weekends. This also is not just a "hoppy" iv picked up over night. I was born and raised into this life style. Ill just say it once more to clarify, this is not a drag car, nor will it become one, Im just making a fun, quick street car. An yes its "just a 305" however i will update all of you in the spring with my e/ts. So far iv shaved over a second off my stock e.t without the NOS. Not bad for maybe a 1000$$ worth of parts....

 

I was actually asking FRMULA88 about his 305 combo before he stepped up to a bigger engine since he ran spray too. He may have some thoughts on this.


http://www.carcraft.com/techarticles/ccrp_9903_305_chevy_small_block_engine_build/

I'm going to throw this build out here as a reference, not for the HP/TQ numbers but rather for where they occur. Notice how a 262H has a peak HP at 5300 with a Vic Jr. While the intake defines this partially the cam does a lot as well.

http://www.hioutput.com/tech/343hp/343hp.html

Next build, this one has a 224@.050 Lunati cam in it, Performer RPM intake and some stock heads with mild work and bigger valves. They're still running 8 degrees less duration than you are. Peak HP is at 6250 RPM.

http://www.hioutput.com/tech/290hp/290hp.html

Here is a 290HP 305. The cam is pretty damn well a stock TPI cam with a narrower LSA. It uses a performer intake manifold and some heavily worked heads. Peak power on this engine with this tiny cam is 5500 RPM.

What I'm getting at here is you have the "race car" parts already in the engine as you put it. You're going to see the behavior these parts provide you at the low end since you have a larger duration cam and a 3000 stall converter and decent gears. Why not try to take advantage of where they reward you up top? Comp rates this cam above your red line (5800) even with a 350. A 305 should see another 500 RPM from it in all probability.

Traction the same, I'd be willing to put money down that tweaking your governor with 500-1000 more RPM before shifting would net you at least .1 in the 1/8th without the bottle, and with an intake like a performer RPM even more. .1 is a hell of a lot of bang for your buck for going to a JY, pulling a governor out of a car and modifying it. If you want to spend some bucks on this, they make a kit for it.

http://www.ebay.com/itm/250-350-400-700-R4-Governor-Springs-Weights-Shift-Kit-/200630818090?pt=Motors_Car_Truck_Parts_Accessories&hash=item2eb687552a&vxp=mtr
Another option is just to pull your current governor out, grind the bottom of the weights about 1/8", use some small nails to replace the pins and put it back in. Grind em a bit at a time, that way you don't go too aggressive. I mean, at what point are you going to see an ET gain for the price of a few finishing nails?

 

Subtract 20-30 percent from those hp figures to get real world figures in our cars turning power steering pumps and alternators and going through factory headers through intakes and filters that fit under our hoods. This is what I think all the 305 guys get all googly-eyed about...

Carcraft has put milled Vortec heads with an xe262 on a 305 and made 325hp on an engine dyno. I have that exact same setup on a 350 at slightly less compression and I'm at an estimated 300-305hp according to teh weight/trap speed calculators. Holley double pumper, Performer RPM, long tubes, etc... and Im still at less hp than their 305 in the real world.

Now make no mistake, in theory, the cam and heads and intake will determine power level, not cubic inches, so I think an xe262 and vortec heads 305 (or 334) setup will make the same power as my 350 will, but I've got gobs and gobs of torque out of the hole, a 305 wont.

 

The Performer RPM "air gap" manifold with a dropped base air filter fits under the stock hood.

IF you want to optimize the car for drag racing either 1/8 or 1/4 you need to optimize the rear gear and the shift point.

Ideally you want to cross the finish line with RPM at the engine's red line..


The 305 and 350 have the same Rod:Stroke ratio so the rev limit is the same. the key difference is the 350 make more TQ which means it will always make more HP. The larger bore of the 350 lends itself to better breathing potential. because larger bore = larger valves = more air & more fuel = more TQ more HP.

The rest of the RPM potential is based on the cam and the valvetrain... A solid lifter cam will typically rev more than a hydraulic, valve springs. etc. etc.

My 383 with a hyd roller cam peaked at 5800 & I fine tuned to governor to shift at 5800
using the B&M governor kit..

My 421 with a solid roller cam peaks at 6800. so I shift manually at 6800.

Next time you race... observe your shift point(s) RPM and the RPM as you cross the finish line and adjust accordingly. For 1/8 mile racing the ideal rear gear may be a 4.56 or higher.

Also for all out drag racing a 700R4 is a poor choice because of the wide ratio.
You want a closer ratio transmission like a TH350 or TH400.

700s (4l60s) have a notorious RPM drop between the 1 - 2 shift.

rather than playing with the engine I would address the rest of the drivetrain to optimize it for your 1/8 mile track.

You may not want a very low rear gear but with a 700 you do have over drive for street use. The low gear will help offset the 1-2 shift and raise the RPM limit as you cross the finish line do that and adjust the governor.. and you will find some ET & MPH..

 

http://wallaceracing.com/Calculators.htm

this is great reference...

focus on the GEAR / RPM calculators.. if you have your timeslip(s) these will help.

 

i agree. throw a bunch of gear at it, and spin the motor harder/higher.

 

Thanks guys ! I do have a shift kit in the tranny and a corvette servo to help that 2-3 rpm flare.
I guess the only reason i havn't pushed anymore rpm out of it is because i want sure how much i should be pushing the stock rotating assembly with stock balancing. I have ran the car to 6k on street and it still pulled without laying over. Also I dont have a limiter on the car. Thanks again!

 

There is in the market a fix for the 700r's second gear drop.Better first to second ratio.

 

The governor assembly has nothing to do with the shift kit or the servo.

The governor controls the shifts points at WOT so if you have not modified yours then it is still shifting per the OEM settings. Probably around 4000 RPM, which is way to low for drag racing. I think I paid 35$ for my Governor kit and it was money well spent because just by adjusting the shift point at WOT the car went over .1 faster !

Your engine does not need to rev past 6000. invest in a MDS box with rev limiter and set it to 6800. better safe than sorry. (MSD start dropping rev about 500-800 RPM before the limit so for 6000 you set it 800 higher..

 

Buddy-my advise is I'm not so sure I would invest in a stroker for it vs a good set of heads and a turbo.That would be the biggest bang for your buck.

 

Now that would be nice ! too bad it has taken this long.

but for a track only car a 400 'glide, or 350 is still much better for durability.

The way I see it if you can't put a trans brake on a 700 (4L60) how strong can it really be??

I had great conversation with Art Carr over 10 years ago about this, no one (not even Art Carr) makes a 'brake for the 700.

You have to wonder why and when you do you will realize / accept the inherent shortcomings of the 700 design for hi-abuse situations.

 

the gearsets to change the 700r4's 1st gear have been out a while , but at 1k-1,200 a pop why bother

few companys did make transbrakes for the 700r4 years ago , it wasnt the clutches that didnt hold up it was the front pump , thats why they stopped making the tb kits for the 700

 

That really wasn't the point I was getting at with this. I don't really trust magazine articles for overall power levels, but at the same time they are less likely to fudge the RPM. E.G. they apply the "adjustments" across the entire dyno run. It's also a swill gas "deep dish" pistoned 305, even the L03s came with less dish than that engine did.

H/C/I will determine power level, CID by and large determines where it comes in at all else being equal. That's just as valuable of information. A 400 with an H/C/I package is going to be way different than a 305 with the same H/C/I package because it's going to want to make its power at a different RPM and therefore likely need different gears and converter. It's not just about raw power but how it's used too.

In regards to the redline of the stock assembly, it's modern with lighter weight pistons. It's really hard to say what a safe rev limit is, I'd be trying to bring the RPM up slowly at the track and see where it takes you. Valve float and piston to valve clearance may be an issue, especially if you didn't check. Since it sounds like you have "built motor" on the mind, I wouldn't be too afraid to experiment with this one a little. You can probably learn a lot about where you need to go with the next engine no matter what it is or what size bore it has.

Start bumping your shifts by say 200-250 RPM at a time, see where it gets you at the track. Your MPH and ETs will show where you're making power at or not making power at and where the engine wants to be. At some point that intake WILL make you hit a wall, but chances are you're not there yet. The 700R4 may be a bit of a challenge powertrain wise, but if you were to swap it out I'd do a 200R4 to keep streetability and get better ratios. Personally I'd worry about getting the rest of it lined up right now. The idea is to tune it, just like you would a carb or ignition timing and not assume that X Y or Z RPM is going to do well for you.

That gear ratio calculator is a great tool, I can see why you'd want the 3.73s with a street driven car though. One warning is that it does neglect converter slip, so you need to keep that in mind as well. Going crazy with the gears and to a 3 speed is very much an opinion of "street vs race" though, so think about it before you do it.

If you want to build a 305, my build for spray would be:
-.060 over (I usually pick up 305s for $50-100, who cares if you junk a block.) Roller preferred, Vortec is okay but so is TPI/TBI.
-Eagle SiR rods (hey they've been run to 600hp and 7K with the good bolts, not a bad deal)
-Forged slugs if you want to spend the bank, some Speed Pro hypers otherwise. Flat topped in this case
-Shaved Vortecs or 305 Vortecs. L98 Aluminums are another good option or if you're a person into kludging like I am you'd end up digging up some LT-1 heads and filling the reverse cooling passages and redrilling em. Ported 416es are another good option for iron. No not going to run 8s but still can be made into good performers. Anything with low 200 CFM flow is going to do what you need it to on a low 300 CID engine so some milled Vortecs would work great even stock.
-Cam is a bit hard, I'd love to see where your real power band turns out to be with that one.
-Performer RPM or Vic Jr. intake. Both of which have similar cross sectional area by memory. The RPM should be more streetable being a dual plane though you could always try to add a divider to the Vic.
-Your gears look pretty good, your converter may need work. I would want to run it at the track and see where it goes. The gears aren't going to be for all out racing but good for all around. If you can't get the 60" down you may need to restall it. I'd be talking to a pro at that point though.
-Traction. Tires, LSD suspension tweaks the whole mess. The idea would be to try to get the 60 down as much as possible especially on spray.

 

Thank you for all the info, Just to answer and above question, i manually shift the car.
I think my gear ratio is just about perfect for the driving I do, considering its a street driven car and on 26 in tires. My 60 foot is 1.75, personally im pretty dam impressed there. I have kinda been thinking about some 4.11's but really not sure about them on the street. But i know id see a good e/t difference.
My machine shop can get me a 400 crank, rods and Hyp. 7cc dish pistons with 2 valve reliefs, He can sell me all the parts plus the cost of boring the motor .030 over for $980 then i'll pick up a rpm intake and may see where its at from there. Cars in paint shop now plus Im up in Maine so I have at least till the end of April before I can even try car on the street. So I'm just trying to get my build figured out.
I think for now until i can find a set of heads I may do a little more port work on these ones and try them for now. valves and springs are all new and heads have been milled and had some light port work done already. I know they wont be optimum but i may hold out till middle of summer an get some Trick flows.

 

as I said once you realize / accept the shortcomings of the 700 you will understand why it's not the best choice for a max effort drag car.
blowing the front pump with a trans brake is unacceptable.


I hung on to my 700 for a long time, it lived a good life behind the 383 with 1 rebuild in 10 years to due to worn clutches. but that was only 465 HP

so I ditched it for the TH400, with a 'brake and Cheetah shifter. Absolutely no regrets.

that is not a bad price to pay for the 1st gear swap if you had a good 700 and wanted the closer ratio..

but in retrospect you can build a 400 to handle 800+ HP for that price. LOL you give up the OD but gain the durability.

 

Do get me wrong.We have run glides for a very,very,longtime in drag race only applications.The GM cases have there limits and the reason why your finding aftermarket cases for glides.It is there where the expensive glides begin.

 

Don't skim over this post.It cuts right to the bone how to go about what to do.

 

If you can be into a short block for a grand, that is not bad at all. With flow you can get from ported 305 heads you still have head room (no pun intended.) Cant wait to see what she does. Worry about the converter and gears till after you get in a few visits to the track imo. You will have a better idea where you need to go with them.

 

Hear ya!
After fooling with sbcs for way too long even with the stout 383 I have I still miss that BB torque. Have a potential buyer for my 383 now if he pulls the trigger a rowdy 496 os going in or bigger. Oughta be fun. Hp AND tons of low end too.

 

On the other hand you can now build a pretty large LS based engine 427 + cu in. and not have the headaches shoe-horning the BBC into to this chassis.

Great factory LS heads with 15 degree valves.

but still hard to beat a NA BBC over 500 cubes for raw power

but for each second faster than 10s.. it just cost so much more. Not just to build the car, but to maintain it.

yes N20 can get you there cheap, but past a 300 HP shot the wear and tear on the parts can be brutal, especially if you go lean . Turbos and blowers cost more but the consequences of bad run are the same.

At some point we all have to draw the line to race at a level we can afford.

 

The thing I always contend is on the street hp isn't all that and a bag of donuts.Torque is the driving force for most street vehicles and a primary question is where that torque curve begins at what RPM??. How big a engine is the determining factor. So hands down the BBC's are going to run over most anything else.Then the 400's,383's,LSx's,355/350's.So to compare a LSx to say a 383 is akin to comparing apples to oranges.Main reason why is the LSx engines tend to operate best in the higher RPM ranges.