When upgrading timing chain for cam...the LT4 timing set requires opti upgrade to vented....what if I went with a heavy duty timing set that was non-LT4...would I need to upgrade anything else?? If this is stupid...sorry....

 

My car has 25k....I dont wanna swap opti's....what timing set is best?

 

i'm in the same boat as you. i have a 93 w/ 25k miles and a nearly new non vented opti on the car, and i'm about to do heads and cam. unfortunately our only options without replacing the opti are stock and the lunati(which from what i hear is at best only as good as a stocker).

 

So....there is no heavy duty timing set that we can get for the non-vented opti setup? That blows I really dont wanna spend the $$$ on this upgrade

 

Will the stock timing set hold 400+hp?

 

from what i have seen, yes, but the bigger question is, for how long. i also suspect it's more rpm dependant.... as in 400 hp at 6000 - no problem vs 400hp at 6400 probably a problem. i'm planning to go with a cc306 or ex233/239, so i'm probably in the rpm range where i should most likely upgrade to be safe(plus i run a 125 shot also).

my friend has a 94 with a cam(similar to 305/hotcam) and heads and 125 shot. he replaced the timing set with a new stock set when he did heads/cam and has been just fine for quite some time... but he has his rev limiter set at 6000.

 

I really dont plan on reving higher than 6000rpm. I am going with a 227 or 230....a custom ground cam.....I think he stock timing will do....for now that is...

 

I wouldn't trust the stock set. Mine had a ton of slack in it.

 

That's good advice maybe, but what other viable timing chain options exist for the unvented opti, w/ or w/o the oem water pump? This is frutrating that no one has developed a high performance timing chain for use w/ the unvented opti. Lunati has an aftermarket timing chain for this application, but not alot of positves about it on this board. So we're left with: oem; Lunati; or change to a vented opti and the timing chain world becomes your oyster . Or is it that the oem timing chain IS ok for say, up to 450-500 rwhp @6000-65000 rpm, and we're in better shape then we are led to believe?

 

Wish we had a straight answer on this.new Opti's are expensive and used are questionable.....

 

As someone pointed out to me the other day, this (scroll down) from DRM. Before you get too excited, it is $366 for just the cam gear. Nonetheless it is an option. Their chain is pretty stock looking. It does make the vented opti conversion look a little more inviting, though.

 

Alright...who's got that link for the opti upgrade...part numbers and all....

 

Parts from jason cromer

> 95' Front Cover 12552426- $67.00
> Vented Opti 1104032- $215.00
> Vented Opti electrical harness 12130319- $73.00
> Vented Opti vented vacuum harness 12555323- $13.00
> 1LE Elbow for vented opti 25147187- $48.50

$10 shipping total


that's from 1 post

and this is from another:

I just bought an opti from dal - $196
extreme duty "ED" timing set $205 from jason Cromer
'95 timing cover and gasket $57 jason
vacume hoses/elect - ~$80 - you can fab your own


most cams come with the long pin required fror the "95+ opti

note: your stock cam will not work with a vented opti.



and here's a link:

http://para.noid.org/~muttvette/opti.html

 

They are proud of their stuff!!! Must know they currently have a monopoly on the market! Think I will stay w/ the oem timing chain until a more cost-effective one enters the market. Thanks Shoebox!

 

Buuuuut....will a cam upgrade(230/236) be compatible with the not-vented opti????