So I've been doing some research and I have found on 2gnt and 'tuners people referencing to the 4g63 valvesprings by crower fitting the 420a head. I was wondering if this was just a simple replacement or if there was any modifications to the 420a head to do this. Thanks for all the help. ~Chris~

Define simple ;-)

Just a straight up spring install. No modifications needed. I'm running the stock 4g63 springs in my turbo car and the Crower's 4g63 in my NA.

Thank you very much. That is exactly the info I was looking for. Now what are the benefits of using the crower springs for the 4g63 vs. the crower springs for the 420a? Are they the same dimensions, have the same rates or ae they just better?

Originally posted by ckellum2
Thank you very much. That is exactly the info I was looking for. Now what are the benefits of using the crower springs for the 4g63 vs. the crower springs for the 420a? Are they the same dimensions, have the same rates or ae they just better?

They are cheaper IIRC.

At CI Motorsports the 420a kit with titanium retainers is five dollars more than the 4g63 kit.

Originally posted by ckellum2
At CI Motorsports the 420a kit with titanium retainers is five dollars more than the 4g63 kit.

Whoa, slow down there a little. The SPRINGS are the same size from 4g63, but the retainers etc. are different.

And you may want to check out the FS section for some opinions on CI Motorsports (i.e. under the Bad Guy section). You're call.

Thanks for the heads up. So what I am understanding is; get the 4g63springs, and the 420a retainers. And what kind of selection for valves are there?

So what are some good retailers/vendors I should check out also? Thanks.

yea it will work but no poin in doing it just get the 420a crowers

CI is definitely slow on shipping, but they AREN'T bad guys. Don't expect next night shipping, wait 2 weeks or so, but if you're not in a hurry, i'd do business over and over and over.

Originally posted by nicho919
CI is definitely slow on shipping, but they AREN'T bad guys. Don't expect next night shipping, wait 2 weeks or so, but if you're not in a hurry, i'd do business over and over and over.

It took a month for me to get my 420A Crower springs from them (would still use them though)... If I remember correctly, Modern Performance also has a listing for them for a lot less.

So is it all 4g63 valve springs are the same or is it just the crower's? Because I just found on vivid racing a set of Brian Crower's are 73.13 dollars! Thanks for the help everyone.