348 engine to 380 in 55 Chevy

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GreenEyez93274

Well Known Member
Currently working with 348 complete with 690 heads. Yes i know those are the big heads for 409. He had this combo for years. Bought the engine 45+ years ago out of 64 impala. The block is 3755011 with a date code 1/28/58. Suffix code TI028HA which is 280HP with 3/2 and power-glide. As far I know the engine is STD and never been overboard. Also have extra set 379 heads to.
The engine is installed in 55 Chevy Bel Air. Have took the engine out and installed the new 3/4" forward mounts from Earle Williams with 1/2" side shift to right for steering box clearance. Plan on installing 500 CPP power steering box and ditch the manual box. Gonna mate to 700r4 and go automatic. Bought a transmission crossover from Earle Williams to. It was 4 speed before. Using stock exhaust manifolds also.

Need a 409 crankshaft and connecting rods as starting point. Horsepower wise I'm thinking 400? Compression i say 10/1 since it 9.5/1 right now. Any more help or ideas would help since Don has already pointed me in a better direction. Thank you.
 
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Don Jacks

Well Seasoned Member
Supporting Member 3
400 hp is going t be hard to achieve with 2 1/2 inch manifolds,if you've got the 2 inch outlet stuff,forget it.Use the 690 head.What are you planning on for induction? I don't know if it has sold yet but a member very recently posted an Edelbrock large port single 4 bbl.manifold for about 100 dollars less than what a new one would cost today.The piston rod combo will put you in the 10-10 1/4 CR range.Comp has a new hyd.roller cam that will put you in the one hp per inch range with 2 1/2 manifolds,4-410 with headers.It will get you decent mileage,drive daily if needed,and be very throttle responsive[fun] to drive.
 
1964SuperStocker

1964SuperStocker

Well Known Member
Supporting Member 3
With 690's you could hit 400hp without having to put a stroke of any kind. Good intake and camshaft and might do it with the 9.5:1 but 10:1 would do it easy. Now that I think of it, the 690's should bump your factory 9.5:1 up too. You should have better than 9.5:1 compression and good flowing heads.
 
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1964SuperStocker

1964SuperStocker

Well Known Member
Supporting Member 3
Don Jacks said:
400 hp is going t be hard to achieve with 2 1/2 inch manifolds,if you've got the 2 inch outlet stuff,forget it.Use the 690 head.What are you planning on for induction? I don't know if it has sold yet but a member very recently posted an Edelbrock large port single 4 bbl.manifold for about 100 dollars less than what a new one would cost today.The piston rod combo will put you in the 10-10 1/4 CR range.Comp has a new hyd.roller cam that will put you in the one hp per inch range with 2 1/2 manifolds,4-410 with headers.It will get you decent mileage,drive daily if needed,and be very throttle responsive[fun] to drive.
Click to expand...
Yep, don't want to forget those headers and be sure to match your carb to your build. Don't just throw anything that bolts on. LOL!
 
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GreenEyez93274

Well Known Member
After looking at the block, heads and intake I did noticed that the heads are 583 and not 690. I remember my dad saying he had a different cam instead of stock one. Ill have to ask which one or if he even remembers. Intake is a 3814678 and exhaust is 3732793/4 which are the small exhaust for 348. Ill be uploading some pictures of the block and casting/suffix/date numbers shortly.
 
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GreenEyez93274

Well Known Member
Yep Don. Those exhaust manifolds are gonna have to go. I talked to my dad more and he said when they pulled the engine out of 64 Impala it had the bigger exhaust ( the ones that dump to the rear) and I think he said they didn't fit right in his 55 chevy at the time. Hench the smaller manifolds.
Oldskydog I noticed what you meant too about the capital "I" in the suffix code.

BTW I forgot to mention this engine still in running condition when we pulled it out.
 
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Don Jacks

Well Seasoned Member
Supporting Member 3
Great,now do the fresh short block,go through the heads with new stainless valves if it doesnt already have them and then we can look at cams.What are planning on for rear end gearing and tire size? That'll help with the cam selection.
 
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Robert Jacobson

Robert Jacobson

Active Member
Interesting reading. I didn't know about the 3/4 inch forward engine mounts and the 1/2 inch offset. These things were probably not available when I installed my 409 in my 55 Chevy. I used the stock 55 small block bell housing to use the stock rear mounts. My firewall was already notched because I had to make reliefs for the prior engine, a 427 BBC. The steering box was a problem. I still run the stock box. It was a real pain building headers on the driver side. Had to make (modify) the intermediate steering bar that swings between the idler and pitman arms as the 409 oil pan hung to low.
 
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GreenEyez93274

Well Known Member
The 348 block was installed in my 55 Chevy using rear bell-housing mounts. The firewall was knocked on driver side where top of the head hit the firewall. The front of block was mounted using factory front style mounts. Holes were cut in between 6 cylinder and 8 cylinder holes in the cross member. Ill take some pictures of the mounts and 1/2 side shift. Mounts are tacked in placed for now depending if any changes occur from now into the future. The front part of the bottom oil pan was cut and moved back for clearance of steering center link.
I have article or guide that someone wrote from another forum about installing 348/409 in TriFive Chevy. Your more than welcome to look at it
 
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