5abivt

Ok I need some info and advice on choosing a distributor. I know the pre lt1 cars had them and it appears that some hei distributors I see online have a coil built right on top of the cap..

I need a distributor that has no advance or can be locked out.

Are the coil on cap dizzys any good? A coil there would eliminate a long could wire i use which I can imagine is a good thing.

Any advantage to a large vs small cap? I am fairly certain I can fit a large one behind the ltx manifold.

I basically want the best dizzy to provide spark only and is reliable and balanced for 8000 rpms. Any bearing type recommended?

Since I've been an opti guy and have never had a dizzy equipped car I pretty much know nothing about them so I was hoping you guys could fill me in.

boostedmaxPSI

I have no personal experience with this product however, I do have a buddy that has an 1100hp Callaway Twin Turbo with an LT1 using it and seems to be fine.

http://www.delteq.com/

http://www.nelsonracingengines.com/c...rbo-Vette.html

5abivt

Delteq is a great product but Im spinning beyond the stock computers capability so I had to go aftermarket ecm and i chose gen 7 and removed the opti completely. i would guess that 1100 hp LT1 doesnt rev to 8500 rpm.

rklessdriver

HEI with the coil on the cap is not the best idea for a racing engine. Plenty of people make them work but having the coil and all it's heat generation right on top of the spark distribution is not the greatest idea. Packaging wise it is great thou, just hook up one switch on hot wire and your ready to run.

Small cap v/s big cap. The bigger cap is always better. A bigger cap spreads the terninals out further apart and reduces the chance of crossfire and spark jump off the rotor. As long as you can find room to package the larger cap you always better off with it.

Crane, MSD, Mallory, Accel all make good distributors. I know MSD's have a feature so that the advance mech can be locked out by simply flipping the weights over. In some stock type class racing where we can't use aftermarket dizzys we just lock the advance up with a TIG bead.
Will

USAsOnlyWay

Will is there a certain RPM where you start seeing spark jump with a small cap? I've heard about it tons but never seen any ill effect personally. I'm thinking 6500 RPM must not be enough.

I'd agree with you but in terms of manifolds, HSR, XT and modded LT1 (not sure on that last one) all need the small cap so packaging would be my primary concern.

rklessdriver

No definate RPM range. It all depends on so many variables, it's impossible to go into where the smaller cap is going to be at a disadvantge. For most people it never will be.

Plenty make the small cap work just fine. From a practical standpoint that's all that will fit at times.... Packaging is huge part of the deal.

Will

USAsOnlyWay

Indeed. Thanks for the reply, I'll just consider myself lucky to not have problems.

troutster71

If I read this right, you've got a modified LT1 intake, ready for a rear
mount dist. You also are using Accel Gen 7 ecm, correct?
You want to stay sequential, right?
If it was me, I would go with either dist, modified to be cam signal only, and an MSD (or equal) crank trigger. More stable than a pure dist, especially at 8000.

I've researched it, it can be done. I have a 90 L-98 in my '67 roadster, with old school GEN 6. If I ever upgrade ecm's, I'll go with a crank trigger and a cam signal.

Good luck, keep us posted. GA

5abivt

Thanks for the input guys. My last motor did run a dual sync from accell that gave both inputs. I am going to run an ati magnet shell for my damper with an msd pickup for crank signal. For cam I am planning using the efi connection lt1 cam sensor housing which bolts in place of the optispark. That gives me can and crank and therefore the dfi will run sequential .

If it works as planned Then I can use a distributor designed for high rpm accuracy and durability without the fancy electronics inside. Cost is of no concern my visa company loves me

JackDidley

You can use a big cap HEI with a remote coil also.