[Builtnotbought2010]

Hello to all, I have a situation that I cannot seem to figure out, hopefully someone can shed some light. I know that a 350 would've been a better deal, but I already had this 305 and wanted to experiment with, so don't yell to much lol. Anywho, here's the deal, chevy 305 brand new rebuild, it has flat top pistons, cam is 234/234 @.050 .488/.488 lift , edelbrock performer 600cfm, holley street dominator intake, msd distributor (streetfire), stock heads, stock crank, th350 transmission, stock torque converter, I maybe forgetting something not sure. Anyway, It will start up perfectly and idle perfect, BUT when you put it in gear it will either bog out terribly, or more often it will stall out. I just can't figure out what I'm missing here, this is a new build with less than 25 miles on the engine and holy geez it is being a pain. Any help with this issue would be VERY appreciated, I'm at a loss. Thank you in advance.

[ericnova72]

Cam is wayyyy to big for a 305 and a stock torque converter, you will need 2500 stall minimum and likely 3000 stall. Stock converter isn't "loose enough" for that small engine and that big a cam duration, heck a 350 with 2500 stall converter will have a tough time idling in gear with that cam.

You can try locking out the distributor mechanical advance so that it is fixed with no curve, and set it to 34-36 degrees initial timing and see if that helps, if it does it gives an idea of what to look at next.

[Builtnotbought2010]

Thank you for the reply. Let's assume I put in the proper stall converter, would it still be o.k for my engine in terms of driveability ? or would it be a bad idea with the cam being so big. I just don't want to cause any damage. When it comes to my msd, do you mean just hook it to a constant vacuum other than the timed port or do you mean something else. I'm not to good with the mechanics of a distributor.

[ericnova72]

The stall converter will not really hurt driveability unless you go way too loose(like 4000 stall), in your case a higher stall is needed to prevent lugging of the engine, the cam you installed doesn't really start making any decent power until 3000 rpm in a 305.

Locking out the distributor means to remove the rotor and disable the mechanical advance(the weights and springs). Easiest way to do this is by removing the weights and springs and securing the mechanism at full advance, using a pair of plastic zip ties around each end of the plate. Reinstall the cap and rotor, then set the timing to 34-36 ° and test if it will idle in gear. If it will or is better it points to needing to modify the distributor for more initial timing advance.

Cam of that size will need a lot of timing at idle in a little 305.

[cobalt327]

Originally Posted by Builtnotbought2010

Hello to all, I have a situation that I cannot seem to figure out, hopefully someone can shed some light. I know that a 350 would've been a better deal, but I already had this 305 and wanted to experiment with, so don't yell to much lol. Anywho, here's the deal, chevy 305 brand new rebuild, it has flat top pistons, cam is 234/234 @.050 .488/.488 lift , edelbrock performer 600cfm, holley street dominator intake, msd distributor (streetfire), stock heads, stock crank, th350 transmission, stock torque converter, I maybe forgetting something not sure. Anyway, It will start up perfectly and idle perfect, BUT when you put it in gear it will either bog out terribly, or more often it will stall out. I just can't figure out what I'm missing here, this is a new build with less than 25 miles on the engine and holy geez it is being a pain. Any help with this issue would be VERY appreciated, I'm at a loss. Thank you in advance.

A basic modification that may help, is to connect the vacuum advance up to a "manifold" vacuum source (aka "full time" as opposed to "ported" vacuum that only operates above idle).

This increases the engine speed and increases idle vacuum. After lowering the idle speed to the highest that you can tolerate, try that to see if it's even close to being acceptable.

If not, it's off to buy a looser TC and/or a smaller cam.

Good luck.

[pepi]

Originally Posted by ericnova72

Cam is wayyyy to big for a 305 and a stock torque converter, you will need 2500 stall minimum and likely 3000 stall. Stock converter isn't "loose enough" for that small engine and that big a cam duration, heck a 350 with 2500 stall converter will have a tough time idling in gear with that cam.

You can try locking out the distributor mechanical advance so that it is fixed with no curve, and set it to 34-36 degrees initial timing and see if that helps, if it does it gives an idea of what to look at next.

Stall converter indeed ...... and 3000 - 3400

[11echo]

Check the vacuum modulator on your trans! IF it's leaking or the diaphragm is ruptured, it'll have that problem. Good Luck!

[Builtnotbought2010]

Good morning everyone, I wanted to stop in and let you know I didn't forget anyone, I am a firefighter and have been really busy. Anywho, I am trying out everything that everyone said and I feel like I'm atleast getting close. I did have to replace my vacuum line from the trans to the engine it was just a mess and I think it was leaking somewhere, it was a nightmare. I put that line straight into the manifold to make it full time vacuum, it did clear up a little bit. I'm gonna play with the timing and the distributor today to see what happens. I'll stop back in for an update. I want to thank you guys for everthing.

[Builtnotbought2010]

Good morning, I think a torque converter is gonna come into play after all. I have done all I know how to do and what you have all said to do. It did clear up alot of what was going on, but it does still act stupid at a red light or whatever. Could anyone tell me a good website to go to for a torque converter ?? Thanks again for everyones advice, I appreciate that.

[eric32]

check out jegs.com they have some good deals on stall converter's. Below is a good one from jegs. I got a jegs 2000-2200 stall for my 350 build and I have had excellent performance from it so far with no issues.
http://www.jegs.com/i/JEGS/555/60403...oductId=750793

That is a good price for one. I had the same problem you did cause cam was too big and after I went down on my cam size all problems went away. Hope that helps you out.
Eric

[Builtnotbought2010]

Hello all !! I finally just got done putting the high stall torque converter (3000 r.p.m) in, and it did absolutley nothing. It is acting the same way now as it was before I changed the converters. I am completly at a loss here. Do you have any idea's as to what I may be missing ?? Thank you.

[eric32]

Its been a while since I read this post but how much vacuum do you have at idle? I have a 350 and run a 3000-3500 stall converter and am running a proform 650 vacuum secondary carburetor and before I swapped out the cam that is in it now I did have a comp big mutha thumpr cam and it had a 102/106 LSA and I only had about 6 inches of vacuum at idle and if I did not hold my foot down just a hair on the gas pedal then it would quit every time.

The reason why it quit was the lack of vacuum signal when going into gear and also not enough stall. Once I swapped out to a cam with a lot less duration and overlap man it made a world of difference.

Now for your situation a cam that size will be much bigger in a 305 then a 350 as how it responds wise etc.

I can't say how much but I would think with your 3000 stall converter it would have helped out a lot compared to what you did have. Hopefully some of the ones who know more on here will help out with more.

Sorry I can't help out with more but if you have a vacuum gauge post what you have at idle.
Eric

[tnsmith10]

Originally Posted by Builtnotbought2010

Good morning everyone, I wanted to stop in and let you know I didn't forget anyone, I am a firefighter and have been really busy. Anywho, I am trying out everything that everyone said and I feel like I'm atleast getting close. I did have to replace my vacuum line from the trans to the engine it was just a mess and I think it was leaking somewhere, it was a nightmare. I put that line straight into the manifold to make it full time vacuum, it did clear up a little bit. I'm gonna play with the timing and the distributor today to see what happens. I'll stop back in for an update. I want to thank you guys for everthing.

if you found trans fluid in the vacuum line from the trans, the modulator will need to be replaced, not just the line. and for an auto trans that uses vacuum, your going to want it on full vacuum all the time.
on a side note, theres a couple other things to look at as far as dying when putting the trans into gear, 1st would be weak spark or a bad module(not likely with a msd), or the jetting and/or needles arent right and the engine may be loading up when put into gear. how do the plugs look?

[MRTS33]

Seems like it would be cheaper and a much more enjoyable car to drive if it had a better matched cam in it. Just sayin.