Going freshen up 420's
08-12-2015 | 10:52 AM
#11
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I'm thinking about pulling the motors this winter, hour meter is a 800. They are 420hp 454's, other than dropping on a set of blowers what is the best way to increase power but keep reliable? I'm not opposed to blowers but it might be overkill for what I'm looking for. Formula 311 with TRS drives. I know it's a very vague question, I have built many SBC and a hand full of LS gen 3 motors but not much with BBC especially marine. I gave up the race car for boating, not to save money just something different. Lol
08-12-2015 | 02:10 PM
#14
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From: dfw texas
If i remember that 420 had some weird one off cam numbers and riser -manifold sets
If the roller rockers still have some life to give and the gen 4 heads havent cracked a bob roller cam and a real exhaust manifold with divided runners should wake it up good. Your old exhaust if not corroded will bring suprising almost gil money to the trs boys wanting to stay with cast
If the roller rockers still have some life to give and the gen 4 heads havent cracked a bob roller cam and a real exhaust manifold with divided runners should wake it up good. Your old exhaust if not corroded will bring suprising almost gil money to the trs boys wanting to stay with cast
08-12-2015 | 02:24 PM
#15
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That is a good idea. The ones that are on it look new or recently redone. I'll have to wait and see what I find. I'll probably have the heads checked out and decide where to go from there. I could probably sell the heads and manifolds (if in good shape) and go AFR and headers. I ran AFR's on my LS motors in the off road race car and was real happy.
08-13-2015 | 01:32 AM
#16
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Joined: Oct 2000
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From: Omaha/LOTO
Lots of options for upgrading the 420's. It really depends on what your HP goal is and how much you want to spend.
Pretty much everything posted is possible but the cost range is from probably 5k to 12k per engine depending on what you want.
420's used the same cam as a 525SC and is still an off the shelf Crane part.
They had Gil exhaust.
Pretty much everything posted is possible but the cost range is from probably 5k to 12k per engine depending on what you want.
If i remember that 420 had some weird one off cam numbers and riser -manifold sets
If the roller rockers still have some life to give and the gen 4 heads havent cracked a bob roller cam and a real exhaust manifold with divided runners should wake it up good. Your old exhaust if not corroded will bring suprising almost gil money to the trs boys wanting to stay with cast
If the roller rockers still have some life to give and the gen 4 heads havent cracked a bob roller cam and a real exhaust manifold with divided runners should wake it up good. Your old exhaust if not corroded will bring suprising almost gil money to the trs boys wanting to stay with cast
They had Gil exhaust.
08-13-2015 | 05:46 AM
#17
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From: dfw texas
I thought i remember seeing some 420's with cast stellings knock offs using gil style flanged risers. Looked just like gils but had a weird riser flange and real long tails really heavy.it was only on the 420 ,maybe it was the 440. Sounds like the op's exhaust has been changed anyhow.
08-13-2015 | 06:22 AM
#18
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From: chicago
I agree with the rest of the guys here. Your money will be best spent, in a new set of heads. All the heads are pretty good nowdays that come from AFR, Brodix, Dart, etc, and will be a nice improvement over the stock heads. The stock heads are too large of a intake runner, poor exhaust port flow, and crappy chamber design. They really arent worth rebuilding imo, when you factor in the cost to rebuild, and performance gain/weight savings, over some new alum heads.
Heres a real basic 454ci , AFR 265 ovals, 950 Holley, 10:1 deal, 609HP at 6000RPM, 575ft lbs at 5000, with a basic off the shelf crane 234/242 hyd roller. I wouldn't be talked into spending 2,000 dollars, to stroke it to a 496ci, that seems so common around here. Your stock crank and rods are fine for that power level. Save that money for heads, cam, lifters, etc.
http://www.airflowresearch.com/engin...-265cc-bbc.php
Heres a real basic 454ci , AFR 265 ovals, 950 Holley, 10:1 deal, 609HP at 6000RPM, 575ft lbs at 5000, with a basic off the shelf crane 234/242 hyd roller. I wouldn't be talked into spending 2,000 dollars, to stroke it to a 496ci, that seems so common around here. Your stock crank and rods are fine for that power level. Save that money for heads, cam, lifters, etc.
http://www.airflowresearch.com/engin...-265cc-bbc.php
08-13-2015 | 07:02 AM
#19
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From: taxachusetts
Heres a real basic 454ci , AFR 265 ovals, 950 Holley, 10:1 deal, 609HP at 6000RPM, 575ft lbs at 5000, with a basic off the shelf crane 234/242 hyd roller. I wouldn't be talked into spending 2,000 dollars, to stroke it to a 496ci, that seems so common around here. Your stock crank and rods are fine for that power level. Save that money for heads, cam, lifters, etc.
http://www.airflowresearch.com/engin...-265cc-bbc.php
http://www.superchevy.com/how-to/eng...al-port-heads/
