BAD-HABIT

358 SBC pushing 350hp @ 5300rpm. I need some suggestions on WHICH TBoltIV box to use? Im using Vortec Heads and 9:2-1 Compression. Factory recomends 30degrees total advance. My engine likes 6-8 degrees at idle. If nobody has a specific TB IV module then what kind of curve should I look for and when should I have total advance in? My boat is a little on the heavy side at about 4400lbs loaded. ANY IDEAS

Ratchet

I run somewhere around 430 HP in my small blocks. Mine ran great with an MSD igniton, with no advance curve. I had the timing at 37 degrees, which would "fade" to about 35 with the merc distributors.

At first, I used the merc distributor, with the MSD box, with no issues.......then, I replaced the distributors with MSD distributors, for no reason / no gain. It's been a while, so I forgot how to wire it, but I don't recall it that hard to do.

You may want to consider this ?

traviss

I ran a 383 around 400 hp last year... I used the stock merc 22 degree module ( 350 mag module). It gave 22 degrees of advance.. I ran my inital timing at 10 or 12.. can't remember. Total advace was around 32 degress. It would gently increase timing up to 3000 rpm then it jump up little by little to get full advance at 4500 rpm..

I will be using the same module and ignition on the new 383 I am building ... around 515 hp.. hopefully

FloridianSon

Traviss do you know if it was the V8-22A or the just the plane V8-22 that was at full advance at 4500.One of them is at full advance at 3500rpm.

BAD-HABIT

If my engine will idle at lets say 8 degrees how much advance should I have (want) and how do you determine were you want the total advance to come in at?

FloridianSon

I think I was trying to help you in your last post about this and I said if you got Dennis Moore's book it would spell it out. I had to do the water test for all three because I did not take my motor to a dyno.If I did I would have known what the best timming was then ,as for the base timming I had to do the water test.The boat is in gear, throttel is at idle and you advance the timming to find the highest vacuum on the vacuum gage, you will have to back off on the idle screw to bring down the idle, just never go so low that the butterflys will bind.For the mid range timming vacuum gage again have you buddy maintain the rpm in question while driving the boat rotate the dis.to find the dis. setting that requires the least amount of throttle oppening to maintain the test rpm and to reach the highest vacuum setting on the gage.This will be the correct amount of advance for that rpm.Then you look at all the modules and figure out what one might fall in your favor.I could not tailor my mid range and on my BBC with some light mods so I went with the V6 module.My motor likes36*for base timming but I run 18* and let the module add the rest.I do feel that the stock 24*module would work fine on my motor and she will Idle at 8*base plus 24*added 32*total but for my cam choise it makes for poor dock handleing. ref.comes from OSO Bible or AKA Dennis,AKA Dennis Moore,AKA Moore.

traviss

Mine I used was the V8-22.. in which has full advance at 4500.. I had just looked it up last week...

FloridianSon

Thanks Traviss Bad - Habit the V8-22 would be my choise.

BAD-HABIT

Why would you want the full advance to come in a 4500 compared to 3500? My old Module was a 24 degree one and If I remember most of the modules listed all came in by 3750Rpm's Key here though is IF i remember What determines where you want your full advance in at

FloridianSon

There is 3.5* between the two around midrange on the V8-22 and V8-22A but that margin might be just enough to keep it away from the ping ping thing and little performance loss. As for what dertermins On mine the cam seems to be makeing the call.I know she wants it, It's just will I give it to her