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My son has picked up a complete and fairly recent reco 253 red motor bottom ( HG 253 bottom end actually ) with blue Brock B cast heads ( casting numbers 92015981 ) and wondering if anyone can tell me whether the B cast heads were made unleaded suitable.

I'm guessing they were VH/VK era heads ??

Heads are still on the motor, I'm re-camming it but not pulling the heads off for a lookey see, as I have only a couple weeks to get this engine in his HQ to replace his smokey oil guzzling 253 in there ATM.

I don't speak commodorish so I don't know a lot about the engines in any of the commodore range.

I only speak Kingswoodish as my interest only lies in HZ's and backwards.

Any constructive help appreciated.

quote:

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Originally posted by HK1837
The only carby heads with flame hardened seats for ULP are VL heads.

B cast heads are probably too big for a 253 in both valves and port work. In my opinion you are better off with normal red heads with exhaust seat inserts.

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Agreed B cast are bit big, then again depends on cam size to. Question.....Weren't standard red heads the same for 253 and 308? Im sure theyre the same part number.

quote:

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Originally posted by HK1837
Yes, except for L34 and any HDT engines with B cast heads the 253/4.2 heads are identical to 308/5.0 for the same timeframe.

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Weren't all VL heads fitted with L34 spec valves?

quote:

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Originally posted by tufgmh

quote:

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Originally posted by HK1837
Yes, except for L34 and any HDT engines with B cast heads the 253/4.2 heads are identical to 308/5.0 for the same timeframe.

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Weren't all VL heads fitted with L34 spec valves?

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Yes, but 4.2L engines were finished by then. Fitting big valves for VL engines was also part of how the compression ratio was dropped for ULP.

Do you have the specs on the cam that was in it?

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Thanks again fellas,

Yep, the seller said 180 RWH so I can only go on that, it may be a piss-in-wind statement, dunno ???

I port matched the inlet manifold to the heads on the weekend with an aluminium burr on a die grinder, the inlet ports on the manifold were way out both in line up with the head ports and in port sizing compared to the head port size. Some ports I had to enlarge up to 5 mm, mainly on the top of the runners.

The cam that was in it was date stamped 10/ 1995 but I can't find any other details of it from the code stamped "090 "( or maybe "060"if I'm reading it upside down ), it doesn't look overly large in lift and duration so I'm thinking there may have been a few extra KW added to the claimed 180 from the seller.

I'm replacing the cam with a cam I have had at home for nearly 30 years.It was briefly run in a 308 in my HQ 80837 coupe I had at the time until I went to 350 Chev.The only thing I remember about this cam is it was a " 30/70 " in the old speak.

It has more lift than the old cam so I'm going to check to make sure that it clears both the pistons and the bore in the 253 before getting too involved in putting the engine back together.

Have bought new sealed power lifters to run on this hardly used cam.

Will report back here.

Thanks fellas.

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Thanks,

The heads are still on the engine and the manifold was the one that was on the engine when I had it running previously on the shed floor. The heads show recent looking machine work on the intake faces as does the inlet manifold so I think the manifold has been machined to match whatever work was done to the heads and block by the previous owner.

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