Topic: engine rebuild/replace options
in Forum: C3 Engines
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So in my previous thread I posted that I'm giving up on getting the bolt removed from the end of the crank. Going to start (OK, continue) thinking about options for rebuilding/replacing. (I've thought about this a lot lately). My criteria:
- Looks and sounds retro, but numbers matching not a priority. To me this means, stock exhaust manifolds, orange block and heads, original valve covers, starter, Q-jet etc. I have an edelbrock performer intake that's painted orange so that's close enough for me.
- Shooting for 300 HP or close. This would need to be done using the criteria above and 9.5:1 or less compression, mild or semi-mild street cam, 1.94 heads, but I do already have true 2 1/2" dual exhaust with Magnaflows.
- Now the tough part - cost. ZZ4's and the like are out due to budget constraints. I think I've got two or three options to fit within the budget, or close.
1. Rebuild my original two-bolt. .030 over, new pistons and crank, new cam kit, re-work the existing heads or find some re-worked heads on craigslist. Many existing parts could stay since they're brand new, such as oil, water, fuel pumps, timing set, etc.
2. Find someone on Craigslist that ran out of money for their project, but already built the motor. Seems far-fetched, but I've run across a few lately that should work with my criteria. I'd insist on receipts for parts and labor and would hopefully be able to get references for any shops used.
3. Find a four bolt bare block and build it from the ground up. Probably my favorite option, but not sure it will fit the price criteria.
Does any of this sound reasonable? Advice? One of the biggest questions I have regards my stock 882 heads. One posting I saw on a different board was that these are the "best of the worst" SBC heads. Is that an accurate description? Are they build-able for 300 HP? And what about the 2 bolt vs. 4 bolt question? Seems like consensus on this site is 2 bolt is adequate for most of our applications with the exception of outright racing.
Sorry for the long post. I'm in the process of organizing my thoughts and this helped. Maybe it will open up an interesting discussion.
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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Lifetime MemberCOPPERAS COVE, TX - USA
Joined: 7/6/2002
Posts: 417
Vette(s): 1972 corvette stingray convertible
2007 coupe
You might think about what I did, I bought a GM crate motor which comes with a 3 year 50,000 mile warrenty. Mine is a 290 HP and all I did was put all my assc stuff on the new motor. When you see the motor it looks original, only a corvette person would know it's not original. The only thing I had to do with the new motor was drill one hole to mount my wire sheilds below the heads, they must have forgot this one because the other side was drilled. I have my original motor all sealed and on a stand along with the original tranny, I went to a 700R4. all this can be put right back in for that all sought out number matching car. Just remember, do what you want because you drive it,just dont do something that cant be undone later.
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
I've seen Fred's car, and the engine does look stock.
Since money is prolly gonna be the deciding factor, I would go with what you have, and build it up a wee bit. Remember, the LT1 put out over 300hp, but they did have a little higher compression, and solid lifter cams. You can still get a hydraulic cam that will work with the 9.5cr, and the heads you have, but the intake and exhaust is really going to determine IF it will meet your "goal" of 300hp.
A 2 bolt block is fine for what you want...
friggin spelchek
Adams' Apple 2011-02-23 10:55:21
Since money is prolly gonna be the deciding factor, I would go with what you have, and build it up a wee bit. Remember, the LT1 put out over 300hp, but they did have a little higher compression, and solid lifter cams. You can still get a hydraulic cam that will work with the 9.5cr, and the heads you have, but the intake and exhaust is really going to determine IF it will meet your "goal" of 300hp.
A 2 bolt block is fine for what you want...
friggin spelchek
Joel Adams
C3VR Lifetime Member #56 
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Thanks, guys. The GMPP 350/290 is a good option - I may consider that in the end. It'd be stretching the budget (looks to about $2K) but a possibility nonetheless. Regarding $$ I know there are other things that will add up: probably will get the Q-jet rebuilt for a better breathing engine, and definitely will do a clutch kit. I'm sure other things will pop up, too. The nice thing about using my existing block for the buildup is I only buy the parts I need.
Fred - so I'm assuming you painted yours orange before dropping it in? Any pics?
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Lifetime MemberCOPPERAS COVE, TX - USA
Joined: 7/6/2002
Posts: 417
Vette(s): 1972 corvette stingray convertible
2007 coupe
yes the motor is painted orange, it's been about 5 years now and it still looks great. I do have some pics but I'll have to find them, not sure which computer I have them on
Crate motors save mainly time- it's an instant pop-it-in deal. Many times, building engines takes way longer than first planned out. Remember, shops need many customers to sustain themselves. Every engine I had built took at least a month to get.
That said, looking at that 290 hp crate is a bargain, but it's pretty tame. Might as well start with at least the 300hp version.
If you find a reasonable shop, build your orginal if you got the time.
I come from a long line of engines and different cars- this is my first Vette, though. I get a sense and hearing all over that the C3's value is enhanced by orginal engine numbers... something you hardly ever see in Chevelles, Camaros, etc.
It's odd but Vettes seem to be in a different league when it comes to swapping parts. Everything is just plain expensive.
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Moses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
When it was time for my tired original smog motor to come out I found a lightly used GMPP 350HO as a replacement. I still have the original motor but with out new heads it was not going to make much HP. If you are going to rebuild your motor, you are going to need better breathing heads. Vortec heads are inexpensive and will increase air flow.
Glen gives sound advice. Vortec heads are available in any junkyard and they are a steal.
Thanks for the discussion. Vortec heads are a good idea and I have considered them, but you need a different manifold for them, don't you? And different valve covers? And do all the stock accessories bolt up? I won't just re-use my original heads as is -- I'll either get different ones or get mine re-worked a bit.
Warp 2 - I grew up in Yakima, my folks still live there. Are there many C3'ers in town?
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Lifetime MemberModerator
Moses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
It does take a new intake manifold, but if you want more HP then an new manifold would be in order any way. You do need new valve covers, gives you an excuse to get something shinny under the hood. Here is what they look like on my engine. The 350HO uses the vortec heads. Here are a few shots of how the parts mount up
in Forum: C3 Engines
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