Head Gasket for 420A Engine

DaFlameking · 10-17-2007, 05:24 PM

Ok, so I've never worked with a 420A engine before and I was wondering, when replacing the head gasket for that type of engine, would I need any special type of head stud.

I know for 4G63 engines, you just get the head gasket replaced and put on ARP head studs to make the labor more easier if you're going to go in and open the block again.

I've even searched and I've found nothing but 46G3 drivers posting replies to the head gasket issues that involve throwing in some ARP head studs pointing me in the direction that they are only recommended in those engines.

Also, I'm thinking about getting a new gasket set at Discount Auto Parts.

So...would I need any special type of head stud and is discount auto parts a good place to get a new gasket for the 420A engine?

Thanks

Rex2342 · 10-17-2007, 05:33 PM

Your going to need to replace the head bolts no matter what. The stretch when they're torqued so once you take them out they are garbage and need replaced. On the 4g63 the ARP's cost as much as the factory bolts and are reusable so thats why we just use them. The last 420 hg I did I had to get the bolts at a dealer but don't remember how much they were. The last 2 HG i've done I just used a set of napa gaskets. I think they were the mr. gasket brand. As long as the head is straight and your not boosting it they should be fine.

Shadow98 · 10-17-2007, 07:45 PM

You can get Felpro head bolts pretty cheap at AutoZone, but if you boosting, I recomend ARP head studs. Reason being, boosted 420A's blow HG's alot easier with bolts then studs. FYI, ARP head studs are expensive when compared to Felpro bolts.

napkinthief · 10-17-2007, 08:22 PM

Careful when putting those bolts in. Dont strip the block threads. Its a real pain in the arse when you gotta drill em out and rethread.

If you plan on boosting, go ARP studs.

If you just want to fix it, go to autozone and ask for headbolts and gasket.

Locke · 10-17-2007, 08:48 PM

It is just like doing a HG on any other DOHC engine.

Note: The driver-side rear bolt hole should be finished with a bottoming tap, or the head bolt going into that hole shortened just a little. The bolt bottoms out early in that hole, which when torqued properly will not load the gasket as it should in that area which has been known to lead to premature gasket failure in that corner of the head.