Jarod_C

I need help with some stats, and info. I'm helping my brother with some decisions on what to go with. It's a 67 Delmont 425 super rocket. If anyone knows stats like combustion chamber size, valve size, ex you whould be a god. I think we found a winner for a rebuild kit, but we still would like to know it's exact compression ratio, and other things before going into the rebuild. Any stats on this car would be a huge help, Thanks.

Oldsmaniac

Factory HP numbers depend on carb. for the most part as well as air cleaner and decal.....A 2bbl engine would have either low compression 9to1 or High compression 10.25 to1....I believe all 4bbl carb engines were HC and the Sfire would have Factory dual exhaust and be rated at 375HP. I know in 66 the HC 2bbl engine was rated at 310 HP and the 4bbl at 365HP. Compression ratio in these Oldsmobiles is determined by pistons.....just change the pistons respectively and you will get the ratio you want.....

Jarod_C

Thanks for the reply. It's 4bbl, and it says "ultra high compression" on the aircleaner. Haven't been into the engine so we don't know what pistons are in it. I'm guessing they're the factory ones. I know he want's to keep the high compression though. The reason why we want to know the combustion champer size is so why can plan on a type of head before we start the rebuild, but if it comes to it we can just measure it after it's off. I remember after buying my 302 I ordered heads for it, and come to find out it had high compression heads already on it plus I found out the pair I ordered were two ccs less. Anyway I'm just trying to save the headache now.

Well while on the subject, does anyone know any good after market parts that are good or some that work well together. Maybe a cam, and head set. We know we're for sure going with a dual plane edelbrock intake.

mikkim129

442.com

Almost anything you need to know about olds
Well most everything

Jarod_C

Thanks, someone else on another forum told me to go to that site. It's a great site, but it has all the info on every engine but the 425 lol. Sucks for me I guess.

texasred

V8 - 425 4-BBL 365@4800 470@3200 4.125 x 3.975 10.25:1
V8 - 425 4-BBL 375@4800 470@3200 4.125 x 3.975 10.5:1
via www.oldsmobility.com

And I wouldn't trust the info on 442.com. It's not updated and notoriously error-riddled.

C.J.

Jarod_C

Well, with some help from this and another forum I found what I was looking for, for the most part. Thanks

There just isn't very much info out there about Delmont, but we know what we wanted to find out before we go into the rebuild. It's says it has 10.5 to 1 ratio, so if it has cracked heads we would have to go with the 77cc heads that bumps it up just shy of 11 to 1. I guess we would want to get some dished pistons if that's the case.

Some of the info on 442.com is a little fishy, but what I needed sounds pretty legit. Oldsmobility.com was a pretty nice reasorce to, but like everywhere else says nothing about delmont. If it's a convertible you can find more then you need to know anywhere almost.

Here's a picture of the car, I had to make it smaller so you can't see the dirt as well. My brother would be pissed if a posted a picture of his car dirty lol. I should have taken a picture of the interior of the car, it's perfect, all original. The wheels didn't come on the car of couse, but the the originals are in the trunk.

The car runs great I think he just wants to get it rebuilt so he can get all the power that's missing back, and then some. Maybe we'll post a pic of it doing a burnout before we pull the engine.



Edit: lol, I forgot the picture was my avatar.

Oldsguy

GAWD that's a beautiful car. Keep it, fix it, and haul butt in it! My reference indicates the there were two choices, the 330 Delmont and the 425 Delmont, there were 16,669 of the 425 models made in the 2 dr hardtop version. The Delmont was a new prefix in '67 and didn't last a long time, I think they only used it two years, then went back to the Delta 88 series again. Also, it appears that the Ultra High Compression was not the standard engine in the Delmont so the original purchaser probably paid the extra $100 bucks for the one in it. The original 425 available in the Delmont was the "turnpike cruiser" 9:1 compression engine, you got lucky!

Jarod_C

It is a beautiful car, thanks. I was jealous when he bought the car. The price he got it almost made me mad, someone shouldn't be able to buy a car in as good of shape that this one's in for 1,500 bucks. Right after he bought it someone told him they would give him 6k for it.

btw, he's a picture of my truck.

It's been collecting dust sense I blew the rearend out of it six months ago. It's in the shed with a lot of junk so I photoshopped some of the junk out. The garage is saved for the lawn mowers. My truck's in shambles.

Oldsguy

Bummer about the truck. Any fun ride should be rideable, when it's not, it's a shame...

Thomas Richards

Mondello Performance. Every part you could ever want. BUYER BEWARE. I built my 1965 425 Super Rocket using parts from Mondello and Summit Racing. Unfortunately since I am not rich it took 15 years to accumulate all the parts i wanted for my build. When the time came for the build a lot of the parts I purchased from Mondello ended up not being compatible with my engine. About a thousand dollars worth. Including reconditioned accessory brackets. Also received an alternator that was rattling straight out of the box. Called customer support/ tech and was told that was normal. That it would "magnetize" once I ran it. Turned out when they pressed the case the brushes were crushed. Since it took so long to accumulate all the parts none of them were returnable.

OLDSter Ralph

Are you aware this original post is 13 years old ? Where is the "Mondello Performance" you got your parts from ?