390 Upgrades

I have a rebuilt 390 in a '65 full size Mercury. It's stock except for an aluminum 4 barrel intake and holley 600 vacuum secondary carb. I'd like to know what I can do to get this to about 375-400hp without changing the short block. Car will be crusing only, and will see highway use. Can I achieve this with headers, 750 carb, Edel RPM intake, electronic ignition and a cam change? What will I see if I replace the heads with edelbrocks (this is a bit out of my price range, but seems the next logical choice)? Any specific recommendations on parts? Thanks!

The short answer is "maybe". If the static compression ratio is high enough to support a more aggresive cam profile and the heads flow well, you can probably do it. I would not purchase any parts until you make a decision on heads, as the type of head and amount of work that you do to them will be a huge factor to consider when choosing a cam.
[addsig]

Using stock heads, your four barrel manifold, headers and a good cam you should be able to get one HP per cu" out of your engine. I know you said "leave the short block alone but you are going to need a new cam to get the HP you want. Summit has a Comp Cams kit # CCA-CL32-221-3 that should come close to what you need. You will need a larger carb to match the manifold, cam and exhaust... A Holley 3310 or other vacuum secondary, 780 cfm carb will do well.
Paul

<font size=-1>[ This Message was edited by: PaulS1950 on 4/27/07 11:11am ]</font>

Hey whats up Chad? Do you have the high or low compression 390?
[addsig]

I think you have a pretty realistic goal

Here is what I would do, in order of importance
1 - Headers and a good free flowing exhaust 2.5 inch, H or X pipe as you prefer
2 - Have the heads pocket ported, especially the exhaust bowls, the ports flow plenty, but the guide area in the exhaust bowl sucks. CJ sized valves if the budget allows. Remember the gains are in the bowl, not the ports
3 - Have the distributor recurved, 12 initial, 36 total all in by 3000

Those three modifications even with a stock cam and your intake and carb will gain seriously significant power, but probably not hit your goal

Next round would be

4 - Edelbrock RPM with a 3310 carb
5 - A cam somewhere in the 230 duration at .050 if you have a 3.50 gear and willing to run a 2500 stall converter. Otherwise limit it to about 224-ish

The numbers will be close and it'll run strong

_________________
70 Sportsroof, 427 FE/489 cid, 10.4:1,Stage 2 Edelbrock heads, RPM intake, 1000 Holley HP, TKO-600, 3.70's, A/C


<font size=-1>[ This Message was edited by: My427stang on 4/27/07 4:53pm ]</font>

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2007-04-27 01:51, My427stang wrote:
I think you have a pretty realistic goal

Here is what I would do, in order of importance
1 - Headers and a good free flowing exhaust 2.5 inch, H or X pipe as you prefer
2 - Have the heads pocket ported, especially the exhaust bowls, the ports flow plenty, but the guide area in the exhaust bowl sucks. CJ sized valves if the budget allows. Remember the gains are in the bowl, not the ports
3 - Have the distributor recurved, 12 initial, 36 total all in by 3000

Those three modifications even with a stock cam and your intake and carb will gain seriously significant power, but probably not hit your goal

Next round would be

4 - Edelbrock RPM with a 3310 carb
5 - A cam somewhere in the 230 duration at .050 if you have a 3.50 gear and willing to run a 2500 stall converter. Otherwise limit it to about 224-ish

The numbers will be close and it'll run strong

_________________
70 Sportsroof, 427 FE/489 cid, 10.4:1,Stage 2 Edelbrock heads, RPM intake, 1000 Holley HP, TKO-600, 3.70's, A/C


<font size=-1>[ This Message was edited by: My427stang on 4/27/07 4:53pm ]</font>
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE> Excellent advice.
[addsig]