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350 to 383 coversion how to.
I asked this question a while back but it was buried in a post, so let me try once more...
I have a 88 350 non roller engine block, rods, and heads. I will be replacing the crank,pistons,pins, all block components aside from block and rods, heads will be stock with new valves, hand porting at least to gasket match, new hyd TQ cam with new lifters and springs.
Assuming I wanted to get a 400 crank, what other tribal knowledge do I need to know to get this together as painlessly as possable? Are the rods good, are the heads ok, do I need special pistons or other work/parts? What is the whole story on making a 383? My target is $1300 for parts and machine work.
Thanks for any help you all give me!
Some decisions are made, questions remain.
OK, I have decided to get the Speed-o-motive 383 kit and add the ballance and the flexplate/spacer. Total is just at $950. This engine is a factory 88 TBI truck engine code "K". I will be re-using the intake, heads, and TBI as well as the factory computer programing. This has been pushed beyound the original planned $1300-$1400 max, but I think we will end up with a much better and reliable engine.
My cam choice is a SBC Crane Compucam/powermax 2030 with Harland Sharp S1002 roller rockers. I am buying the new springs from Crane to match the cam.
Will the factory TBI handle these changes witout noticing?
Will the factory "High Swirl" heads be able to breath well enough to feed this engine to the low max RPM of 4500?
I was told that these are a low flow, high velocity head.
**Bump** Please, any advice on my combo?
I have to get the parts ordered in the next 7-14 days, this is the time to stop me from buying a mistake. Cam, heads, kit, TBI...is this all going to work or be a huge mistake?
Dont unless comfortable with needs
Larry ,
We built these and many other stroke combinations in our shop years before these kits became available. Some combo's are better than others for specific performance goals. With the KITs available it is a plug and play build except the needed clearance issues.
If you are comfortable with areas that MUST be checked then right on- build away. Forgetting to check or grind enough clearance on pan rails - bottom of bore on block and , makes for broken parts.
You can build it and be very happy with performance. If not sure about all needed clearances and if 0.060 will work on bore to rod instead of 0.080 then get help. BTW a big paperclip is about 80 thou and is a must for rod to bore clearance. You can also spot weld paperclip to end of 1/8 welding rod to make easy ,quick tool to verify clearance you have to grind to get to 0.080 in that area.
Parts so far that are nailed down.
OK, here is what I ordered today:
The Crane Cams 114132 (Powermax 2040) cam/lifter Kit $145.40
Crane Cams 11308-1 Spring/Retainer kit $87.45
Crane Cams Crane Cams Gold Race Extruded Billet Rockers 10750-16 for $259.04 $491.89
P.E.P. (1-800-423-2202) Stelite Ex valves $9.59 each or $76.72
New P.E.P. Super Hard iron valve guides for ex $1.25 each or $10
P.E.P. Stainless Performance intake valves (Swirl polished) $5.00 each or $40.
Total so far is $618.61
Next order will be for the rotating assembly, gaskets, 1-peice rear main seal, rings/bearings, Ballancer, and Flexplate. I expect this to be about $1200.
I assume machining will be another $500, so the total will end up being $2318.61
This will be a totally new engine when its finished, and I hope my choices will get us a reliable engine that is more able to withstand the loads being applied to it.
Desktop Dyno puts this engine at:
RPM HP TQ
2000 129 338
2500 165 346
3000 203 355
3500 227 340
4000 232 304
4500 218 254
5000 183 192
These numbers are using a OEM stock SBC flow chart, I will be cleaning up the ex ports and I will also check the intake to head port alignment to see if they need port matched. This is also with stock manifolds and full exhaust. Basicly its a 16% increase in HP over stock, the K code engine is rated at 200 HP peak at 4000 RPM. Based on 200HP at 4K RPM and do the math the TQ was 262 @ 4000, this is making 304 so its a gain of 16% in TQ as well.