import extermination

For what ever reason i cant get my account on rop so ill ask here

till i can save up enough to rebuild my #6 heads, ill have to you what i have.

Its a 77 350 with 3a heads
performer intake
750 demon carb
headers
mallory hei coil

I have a mallory 6a box
(bought from work for $30)

and a nitrous plate kit, 175 shot
(found brand new in a car i picked up)

1st question: does this ignition box replace my hei ignition module?

2nd: what would you recomend me jetting the nitrous down to? Is 100 safe

3rs: how much would you retard the ignition

import extermination

Use what i have**

Darn phone! Lol

oddball

1) You can download the manual for the 6a from the Mallory site. Do that and take a good read.

2) Maybe? Any bottom end work done? Compression still good? That should be a windowed block, so don't expect much from it.

import extermination

Ok thanks.

I guess there is only one way to find out.

Rickman48

Make a bigger window???

import extermination

Yep. Its why god made spare bottom ends

SBORule

You can spray it but I don't think it will last too long.

SBORule

Just retard your timing by turning your distributor counter clock wise.

I would disconnect the vacuum advance hose and plug the distributor and carb where you took the line off.

Set your total timing at 32 degree's which will probably be around 3000 rpm's with a stock HEI.

Rickman48

And wrap a moving blanket from manifold to manifold to keep the oil + shrapnel from your rear tires!!

captjim

Not sure why you would suggest disconnecting the vac advance since N2O should only be used under WOT where vac advance is not an issue.

Nitrous increases cylinder pressure. The compression ratio on that engine is pretty low, so a 75 HP shot really isn't that big a deal. I used a jet combo of 53/57 at 6 psi of fuel pressure and gained 1.2 seconds on my 9 to 1 355. I really don't think that the windowed webs are an issue with a small shot on a 350 at that power lever, IF USED WISELY!!!!

An upgrade to a better box will allow you a boost retard feature. This retards the timing when the nitrous is activated. But again, in this mild application i really don't think it is a big deal.

import extermination

Thanks captjim. Just the answer i was looking for. I was never going to spray 175 on stock bottom end, but was looking for an amount that wouldnt be too risky. So thanks!

As for the box, im just going to run this box cuz i got such a good deal. Any recomendations for the next one i get?

captjim

I had a Digital-6, start retard, boost retard, RPM limiter, no issues except I had to run an external coil with my HEI. That was several years ago, there might be newer, better units out there now.

Just to clarify, IMO there are differences between the windowed 350 and a 403. The 350 had much more meat in the cylinder walls due to less bore and also has lighter pistons. Personally, I would not squirt a 403 though I know that others guys have.