Standard 5.8 351w vs HO GT40

[2001SAN]

Due to a cracked block I'm replacing my 5.8HO GT40.

My mechanic is recommending dropping a standard 351 long block in to save time and money on a small block replacement plus extra costs of pressure testing heads, intake manifold and labour costs for rebuilding. The heads and intake have no visual cracks (but neither did the block).

What is the HP rating on a standard 351w and will I notice a big difference in power? The boat is a 2001 Super air nautique.

I'm in Ireland and the availability of any of these blocks is limited at best.

Thanks,

Darren.

[east tx skier]

Standard 351 is around 260 hp give or take. 351 HO is around 285--290 hp. PCM GT40 is 310.

[Sell]

The std 351 will get a few more hp from putting the fuel injection on. But I reckon you will definitely notice the difference. You could down pitch the prop to improve hole-shot. If you really bomb the old SAN I'd seriously try to keep the hp up

[2001SAN]

I think my plan will be to drop in the standard 351 in. Will the fuel injection i'll hopefully conserve some of that extra power. That will be the quickest way to get the boat back in the water. I'll keep the GT40 heads and get them tested at a later date and hopefully drop them back in for next season if they check out ok. The boat has already been out of action for two months and its killing me! As it stands i'll not be riding with full ballast etc but at least i'll have the option of more power with the gt40 heads at a later date.

[Sell]

Stock ballast and only a few mates & you'll be fine, she may take a bit longer to plane but you'll get to ride.
Be super careful with your wintering to make sure it doesn't happen again.

[2001SAN]

Tell me about it Sell! I have only bought the boat a few months ago. Everything checked out ok on the water test so i'm paying for someone elses mistake! If i wintersed it it would not have a cracked block, thats for sure. If you look at my other thread you'll see the saga in its full glory. Its been a nightmare! I was always super careful with my last boat in the off season but life goes on i guess. The only thing thats hurting is my wallet!

D.

[Mikeski]

Standard 351W + GT40 EFI + GT40 ignition + GT40 heads + GT40 cam + GT40 lifters = GT40 zero power lost

[2001SAN]

This is where i'll show my mechanical ignorance! Everything will be from the old engine will be use but the GT40 heads are not going back in. At least not yet unless I can find a short block but at the minute only a standard 351w long block is available.

Standard 351W + GT40 EFI + GT40 ignition + Standard 351 heads + GT40 cam + GT40 lifters = some power lost?

Are the cam and lifters different in a GT40 than a standard 351w? I though the only difference was the heads, but like i said, i'm no mechanic!

D.

[2001SAN]

Change of heart. Going to get the heads tested and hopefully get them back on a short block now. Seems sensible to try and return the engine to it former glory!

[TRBenj]

Keep the GT40 heads if you can. Ive heard that the GT40 cam was slightly different, but its still pretty small- so I doubt you'll miss it. Nothing special about the lifters.

[2001SAN]

Will be keeping all components apart from the block itself. fingers crossed these heads and intake pressure test ok otherwise its even more money! hoping to know by tomorrow.

[Mikeski]

I thought the GT40 had roller lifters.

The GT40 heads make about a +35HP difference.

[TRBenj]

I thought the GT40 had roller lifters.

Nope. All Ford Windsor marine engines were flat tappet, to the very end.

[Polar Express]

This just might be a bit late, or some might think it ' a given', but maintain your compression ratio as well... Very important when you're talking power, cams, fuel, and the rest of the jazz.

PE